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><DIV
CLASS="SECT1"
><H1
CLASS="SECT1"
><A
NAME="RELEASE-9-0"
>E.10. Release 9.0</A
></H1
><DIV
CLASS="NOTE"
><BLOCKQUOTE
CLASS="NOTE"
><P
><B
>Release Date: </B
>2010-09-20</P
></BLOCKQUOTE
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN108902"
>E.10.1. Overview</A
></H2
><P
>    This release of
    <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> adds features that have been requested
    for years, such as easy-to-use replication, a mass permission-changing
    facility, and anonymous code blocks. While past major releases have
    been conservative in their scope, this release shows a
    bold new desire to provide facilities that new and existing
    users of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> will embrace. This has all
    been done with few incompatibilities. Major enhancements include:
   </P
><P
></P
><UL
><LI
><P
>      Built-in replication based on log shipping.  This advance consists of
      two features: Streaming Replication, allowing continuous archive
      (<ACRONYM
CLASS="ACRONYM"
>WAL</ACRONYM
>) files to be streamed over a network connection to a
      standby server, and Hot Standby, allowing continuous archive standby
      servers to execute read-only queries.  The net effect is to support a
      single master with multiple read-only slave servers.
     </P
></LI
><LI
><P
>      Easier database object permissions management. <A
HREF="sql-grant.html"
><TT
CLASS="COMMAND"
>GRANT</TT
>/<TT
CLASS="COMMAND"
>REVOKE IN
      SCHEMA</TT
></A
> supports mass permissions changes on existing objects,
      while <A
HREF="sql-alterdefaultprivileges.html"
><TT
CLASS="COMMAND"
>ALTER DEFAULT
      PRIVILEGES</TT
></A
> allows control of privileges for objects created in
      the future.  Large objects (BLOBs) now support permissions management as
      well.
     </P
></LI
><LI
><P
>      Broadly enhanced stored procedure support.
      The <A
HREF="sql-do.html"
><TT
CLASS="COMMAND"
>DO</TT
></A
> statement supports
      ad-hoc or <SPAN
CLASS="QUOTE"
>"anonymous"</SPAN
> code blocks.
      Functions can now be called using named parameters.
      <A
HREF="plpgsql.html"
>PL/pgSQL</A
> is now installed by default, and
      <A
HREF="plperl.html"
>PL/Perl</A
> and <A
HREF="plpython.html"
>PL/Python</A
> have been enhanced in several ways,
      including support for Python3.
     </P
></LI
><LI
><P
>      Full support for <A
HREF="install-windows.html"
>64-bit
      <SPAN
CLASS="PRODUCTNAME"
>Windows</SPAN
></A
>.
     </P
></LI
><LI
><P
>      More advanced reporting queries, including additional windowing options
      (<TT
CLASS="LITERAL"
>PRECEDING</TT
> and <TT
CLASS="LITERAL"
>FOLLOWING</TT
>) and the ability to
      control the order in which values are fed to aggregate functions.
     </P
></LI
><LI
><P
>      New trigger features, including
      SQL-standard-compliant <A
HREF="sql-createtrigger.html"
>per-column triggers</A
> and
      conditional trigger execution.
     </P
></LI
><LI
><P
>      <A
HREF="sql-createtable.html#SQL-CREATETABLE-COMPATIBILITY"
>Deferrable
      unique constraints</A
>. Mass updates to unique keys are now possible
      without trickery.
     </P
></LI
><LI
><P
>      <A
HREF="ddl-constraints.html#DDL-CONSTRAINTS-EXCLUSION"
>Exclusion constraints</A
>.
      These provide a generalized version of unique constraints, allowing
      enforcement of complex conditions.
     </P
></LI
><LI
><P
>      New and enhanced security features, including RADIUS authentication,
      LDAP authentication improvements, and a new contrib module
      <A
HREF="passwordcheck.html"
><TT
CLASS="FILENAME"
>passwordcheck</TT
></A
>
      for testing password strength.
     </P
></LI
><LI
><P
>      New high-performance implementation of the
      <A
HREF="sql-listen.html"
><TT
CLASS="COMMAND"
>LISTEN</TT
></A
>/<A
HREF="sql-notify.html"
><TT
CLASS="COMMAND"
>NOTIFY</TT
></A
> feature.
      Pending events are now stored in a memory-based queue rather than
      a table.  Also, a <SPAN
CLASS="QUOTE"
>"payload"</SPAN
> string can be sent with each
      event, rather than transmitting just an event name as before.
     </P
></LI
><LI
><P
>      New implementation of
      <A
HREF="sql-vacuum.html"
><TT
CLASS="COMMAND"
>VACUUM FULL</TT
></A
>.
      This command now rewrites the entire table and indexes, rather than
      moving individual rows to compact space.  It is substantially faster
      in most cases, and no longer results in index bloat.
     </P
></LI
><LI
><P
>      New contrib module
      <A
HREF="pgupgrade.html"
><TT
CLASS="FILENAME"
>pg_upgrade</TT
></A
>
      to support in-place upgrades from 8.3 or 8.4 to 9.0.
     </P
></LI
><LI
><P
>      Multiple performance enhancements for specific types of queries,
      including elimination of unnecessary joins.  This helps optimize some
      automatically-generated queries, such as those produced by
      object-relational mappers (ORMs).
     </P
></LI
><LI
><P
>      <A
HREF="sql-explain.html"
><TT
CLASS="COMMAND"
>EXPLAIN</TT
></A
> enhancements.
      The output is now available in JSON, XML, or YAML format, and includes
      buffer utilization and other data not previously available.
     </P
></LI
><LI
><P
>      <A
HREF="hstore.html"
><TT
CLASS="FILENAME"
>hstore</TT
></A
> improvements,
      including new functions and greater data capacity.
     </P
></LI
></UL
><P
>    The above items are explained in more detail in the sections below.
   </P
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN108973"
>E.10.2. Migration to Version 9.0</A
></H2
><P
>   A dump/restore using <SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
>,
   or use of <SPAN
CLASS="APPLICATION"
>pg_upgrade</SPAN
>, is required
   for those wishing to migrate data from any previous
   release.
  </P
><P
>   Version 9.0 contains a number of changes that selectively break backwards
   compatibility in order to support new features and code quality
   improvements.  In particular, users who make extensive use of PL/pgSQL,
   Point-In-Time Recovery (PITR), or Warm Standby should test their
   applications because of slight user-visible changes in those areas.
   Observe the following incompatibilities:
  </P
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN108979"
>E.10.2.1. Server Settings</A
></H3
><P
></P
><UL
><LI
><P
>      Remove server parameter <TT
CLASS="VARNAME"
>add_missing_from</TT
>, which was
      defaulted to off for many years (Tom Lane)
     </P
></LI
><LI
><P
>      Remove server parameter <TT
CLASS="VARNAME"
>regex_flavor</TT
>, which
      was defaulted to <A
HREF="functions-matching.html#POSIX-SYNTAX-DETAILS"
><TT
CLASS="LITERAL"
>advanced</TT
></A
>
      for many years (Tom Lane)
     </P
></LI
><LI
><P
>      <A
HREF="runtime-config-wal.html#GUC-ARCHIVE-MODE"
><TT
CLASS="VARNAME"
>archive_mode</TT
></A
>
      now only affects <A
HREF="runtime-config-wal.html#GUC-ARCHIVE-COMMAND"
><TT
CLASS="VARNAME"
>archive_command</TT
></A
>;
      a new setting, <A
HREF="runtime-config-wal.html#GUC-WAL-LEVEL"
><TT
CLASS="VARNAME"
>wal_level</TT
></A
>, affects
      the contents of the write-ahead log (Heikki Linnakangas)
     </P
></LI
><LI
><P
>      <A
HREF="runtime-config-logging.html#GUC-LOG-TEMP-FILES"
><TT
CLASS="VARNAME"
>log_temp_files</TT
></A
>
      now uses default file size units of kilobytes (Robert Haas)
     </P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN109002"
>E.10.2.2. Queries</A
></H3
><P
></P
><UL
><LI
><P
>     When querying a <A
HREF="ddl-inherit.html"
>parent table</A
>,
     do not do any separate permission checks on child tables
     scanned as part of the query (Peter Eisentraut)
    </P
><P
>     The SQL standard specifies this behavior, and it is also much more
     convenient in practice than the former behavior of checking permissions
     on each child as well as the parent.
    </P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN109009"
>E.10.2.3. Data Types</A
></H3
><P
></P
><UL
><LI
><P
>      <A
HREF="datatype-binary.html"
><TT
CLASS="TYPE"
>bytea</TT
></A
> output now
      appears in hex format by default (Peter Eisentraut)
     </P
><P
>      The server parameter <A
HREF="runtime-config-client.html#GUC-BYTEA-OUTPUT"
><TT
CLASS="VARNAME"
>bytea_output</TT
></A
> can be
      used to select the traditional output format if needed for
      compatibility.
     </P
></LI
><LI
><P
>      Array input now considers only plain ASCII whitespace characters
      to be potentially ignorable; it will never ignore non-ASCII characters,
      even if they are whitespace according to some locales (Tom Lane)
     </P
><P
>      This avoids some corner cases where array values could be interpreted
      differently depending on the server's locale settings.
     </P
></LI
><LI
><P
>     Improve standards compliance of <A
HREF="functions-matching.html#FUNCTIONS-SIMILARTO-REGEXP"
><TT
CLASS="LITERAL"
>SIMILAR TO</TT
></A
>
     patterns and SQL-style <CODE
CLASS="FUNCTION"
>substring()</CODE
> patterns (Tom Lane)
    </P
><P
>     This includes treating <TT
CLASS="LITERAL"
>?</TT
> and <TT
CLASS="LITERAL"
>{...}</TT
> as
     pattern metacharacters, while they were simple literal characters
     before; that corresponds to new features added in SQL:2008.
     Also, <TT
CLASS="LITERAL"
>^</TT
> and <TT
CLASS="LITERAL"
>$</TT
> are now treated as simple
     literal characters; formerly they were treated as metacharacters,
     as if the pattern were following POSIX rather than SQL rules.
     Also, in SQL-standard <CODE
CLASS="FUNCTION"
>substring()</CODE
>, use of parentheses
     for nesting no longer interferes with capturing of a substring.
     Also, processing of bracket expressions (character classes) is
     now more standards-compliant.
    </P
></LI
><LI
><P
>     Reject negative length values in 3-parameter <A
HREF="functions-string.html#FUNCTIONS-STRING-SQL"
><CODE
CLASS="FUNCTION"
>substring()</CODE
></A
>
     for bit strings, per the SQL standard (Tom Lane)
    </P
></LI
><LI
><P
>     Make <CODE
CLASS="FUNCTION"
>date_trunc</CODE
> truncate rather than round when reducing
     precision of fractional seconds (Tom Lane)
    </P
><P
>     The code always acted this way for integer-based dates/times.
     Now float-based dates/times behave similarly.
    </P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN109041"
>E.10.2.4. Object Renaming</A
></H3
><P
></P
><UL
><LI
><P
>      Tighten enforcement of column name consistency during <TT
CLASS="COMMAND"
>RENAME</TT
>
      when a child table inherits the same column from multiple unrelated
      parents (KaiGai Kohei)
     </P
></LI
><LI
><P
>      No longer automatically rename indexes and index columns when the
      underlying table columns are renamed (Tom Lane)
     </P
><P
>      Administrators can still rename such indexes and columns manually.
      This change will require an update of the JDBC driver, and possibly other
      drivers, so that unique indexes are correctly recognized after a rename.
     </P
></LI
><LI
><P
>      <TT
CLASS="COMMAND"
>CREATE OR REPLACE FUNCTION</TT
> can no longer change
      the declared names of function parameters (Pavel Stehule)
     </P
><P
>      In order to avoid creating ambiguity in named-parameter calls, it is
      no longer allowed to change the aliases for input parameters
      in the declaration of an existing function (although names can still
      be assigned to previously unnamed parameters).  You now have to
      <TT
CLASS="COMMAND"
>DROP</TT
> and recreate the function to do that.
     </P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN109055"
>E.10.2.5. PL/pgSQL</A
></H3
><P
></P
><UL
><LI
><P
>      PL/pgSQL now throws an error if a variable name conflicts with a
      column name used in a query (Tom Lane)
     </P
><P
>      The former behavior was to bind ambiguous names to PL/pgSQL variables
      in preference to query columns, which often resulted in surprising
      misbehavior. Throwing an error allows easy detection of ambiguous
      situations.  Although it's recommended that functions encountering this
      type of error be modified to remove the conflict, the old behavior can
      be restored if necessary via the configuration parameter <A
HREF="plpgsql-implementation.html#PLPGSQL-VAR-SUBST"
><TT
CLASS="VARNAME"
>plpgsql.variable_conflict</TT
></A
>,
      or via the per-function option <TT
CLASS="LITERAL"
>#variable_conflict</TT
>.
     </P
></LI
><LI
><P
>      PL/pgSQL no longer allows variable names that match certain SQL
      reserved words (Tom Lane)
     </P
><P
>      This is a consequence of aligning the PL/pgSQL parser to match the
      core SQL parser more closely.  If necessary,
      variable names can be double-quoted to avoid this restriction.
     </P
></LI
><LI
><P
>      PL/pgSQL now requires columns of composite results to match the
      expected type modifier as well as base type (Pavel Stehule, Tom Lane)
     </P
><P
>      For example, if a column of the result type is declared as
      <TT
CLASS="LITERAL"
>NUMERIC(30,2)</TT
>, it is no longer acceptable to return a
      <TT
CLASS="LITERAL"
>NUMERIC</TT
> of some other precision in that column.  Previous
      versions neglected to check the type modifier and would thus allow
      result rows that didn't actually conform to the declared restrictions.
     </P
></LI
><LI
><P
>      PL/pgSQL now treats selection into composite fields more consistently
      (Tom Lane)
     </P
><P
>      Formerly, a statement like
      <TT
CLASS="LITERAL"
>SELECT ... INTO <TT
CLASS="REPLACEABLE"
><I
>rec</I
></TT
>.<TT
CLASS="REPLACEABLE"
><I
>fld</I
></TT
> FROM ...</TT
>
      was treated as a scalar assignment even if the record field
      <TT
CLASS="REPLACEABLE"
><I
>fld</I
></TT
> was of composite type.  Now it is treated as a
      record assignment, the same as when the <TT
CLASS="LITERAL"
>INTO</TT
> target is a
      regular variable of composite type.  So the values to be assigned to the
      field's subfields should be written as separate columns of the
      <TT
CLASS="COMMAND"
>SELECT</TT
> list, not as a <TT
CLASS="LITERAL"
>ROW(...)</TT
> construct as in
      previous versions.
     </P
><P
>      If you need to do this in a way that will work in both 9.0 and previous
      releases, you can write something like
      <TT
CLASS="LITERAL"
><TT
CLASS="REPLACEABLE"
><I
>rec</I
></TT
>.<TT
CLASS="REPLACEABLE"
><I
>fld</I
></TT
> := ROW(...) FROM ...</TT
>.
     </P
></LI
><LI
><P
>      Remove PL/pgSQL's <TT
CLASS="LITERAL"
>RENAME</TT
> declaration (Tom Lane)
     </P
><P
>      Instead of <TT
CLASS="LITERAL"
>RENAME</TT
>, use <A
HREF="plpgsql-declarations.html#PLPGSQL-DECLARATION-ALIAS"
><TT
CLASS="LITERAL"
>ALIAS</TT
></A
>,
      which can now create an alias for any variable, not only dollar sign
      parameter names (such as <TT
CLASS="LITERAL"
>$1</TT
>) as before.
     </P
></LI
></UL
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN109094"
>E.10.2.6. Other Incompatibilities</A
></H3
><P
></P
><UL
><LI
><P
>      Deprecate use of <TT
CLASS="LITERAL"
>=&gt;</TT
> as an operator name (Robert Haas)
     </P
><P
>      Future versions of <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> will probably reject
      this operator name entirely, in order to support the SQL-standard
      notation for named function parameters.  For the moment, it is
      still allowed, but a warning is emitted when such an operator is
      defined.
     </P
></LI
><LI
><P
>      Remove support for platforms that don't have a working 64-bit
      integer data type (Tom Lane)
     </P
><P
>      It is believed all still-supported platforms have working 64-bit
      integer data types.
     </P
></LI
></UL
></DIV
></DIV
><DIV
CLASS="SECT2"
><H2
CLASS="SECT2"
><A
NAME="AEN109105"
>E.10.3. Changes</A
></H2
><P
>    Version 9.0 has an unprecedented number of new major features,
    and over 200 enhancements, improvements, new commands,
    new functions, and other changes.
   </P
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN109108"
>E.10.3.1. Server</A
></H3
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109110"
>E.10.3.1.1. Continuous Archiving and Streaming Replication</A
></H4
><P
>     PostgreSQL's existing standby-server capability has been expanded both to
     support read-only queries on standby servers and to greatly reduce
     the lag between master and standby servers.  For many users, this
     will be a useful and low-administration form of replication, either
     for high availability or for horizontal scalability.
    </P
><P
></P
><UL
><LI
><P
>       Allow a standby server to accept read-only queries
       (Simon Riggs, Heikki Linnakangas)
      </P
><P
>       This feature is called Hot Standby. There are new
       <TT
CLASS="FILENAME"
>postgresql.conf</TT
> and <TT
CLASS="FILENAME"
>recovery.conf</TT
>
       settings to control this feature, as well as extensive
       <A
HREF="hot-standby.html"
>documentation</A
>.
      </P
></LI
><LI
><P
>       Allow write-ahead log (<ACRONYM
CLASS="ACRONYM"
>WAL</ACRONYM
>) data to be streamed to a
       standby server (Fujii Masao, Heikki Linnakangas)
      </P
><P
>       This feature is called Streaming Replication.
       Previously <ACRONYM
CLASS="ACRONYM"
>WAL</ACRONYM
> data could be sent to standby servers only
       in units of entire <ACRONYM
CLASS="ACRONYM"
>WAL</ACRONYM
> files (normally 16 megabytes each).
       Streaming Replication eliminates this inefficiency and allows updates
       on the master to be propagated to standby servers with very little
       delay.  There are new <TT
CLASS="FILENAME"
>postgresql.conf</TT
> and
       <TT
CLASS="FILENAME"
>recovery.conf</TT
> settings to control this feature, as well as
       extensive <A
HREF="warm-standby.html#STREAMING-REPLICATION"
>documentation</A
>.
      </P
></LI
><LI
><P
>       Add <A
HREF="functions-admin.html#FUNCTIONS-RECOVERY-INFO-TABLE"
><CODE
CLASS="FUNCTION"
>pg_last_xlog_receive_location()</CODE
></A
>
       and <CODE
CLASS="FUNCTION"
>pg_last_xlog_replay_location()</CODE
>, which
       can be used to monitor standby server <ACRONYM
CLASS="ACRONYM"
>WAL</ACRONYM
>
       activity (Simon Riggs, Fujii Masao, Heikki Linnakangas)
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109135"
>E.10.3.1.2. Performance</A
></H4
><P
></P
><UL
><LI
><P
>       Allow per-tablespace values to be set for sequential and random page
       cost estimates (<TT
CLASS="VARNAME"
>seq_page_cost</TT
>/<TT
CLASS="VARNAME"
>random_page_cost</TT
>)
       via <A
HREF="sql-altertablespace.html"
><TT
CLASS="COMMAND"
>ALTER TABLESPACE
       ... SET/RESET</TT
></A
> (Robert Haas)
      </P
></LI
><LI
><P
>       Improve performance and reliability of EvalPlanQual rechecks in join
       queries (Tom Lane)
      </P
><P
>       <TT
CLASS="COMMAND"
>UPDATE</TT
>, <TT
CLASS="COMMAND"
>DELETE</TT
>, and <TT
CLASS="COMMAND"
>SELECT FOR
       UPDATE/SHARE</TT
> queries that involve joins will now behave much better
       when encountering freshly-updated rows.
      </P
></LI
><LI
><P
>       Improve performance of <A
HREF="sql-truncate.html"
><TT
CLASS="COMMAND"
>TRUNCATE</TT
></A
> when
       the table was created or truncated earlier in the same transaction
       (Tom Lane)
      </P
></LI
><LI
><P
>       Improve performance of finding inheritance child tables (Tom Lane)
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109156"
>E.10.3.1.3. Optimizer</A
></H4
><P
></P
><UL
><LI
><P
>       Remove unnecessary <A
HREF="queries-table-expressions.html#QUERIES-JOIN"
>outer
       joins</A
> (Robert Haas)
      </P
><P
>       Outer joins where the inner side is unique and not referenced above
       the join are unnecessary and are therefore now removed.  This will
       accelerate many automatically generated queries, such as those created
       by object-relational mappers (ORMs).
      </P
></LI
><LI
><P
>       Allow <TT
CLASS="LITERAL"
>IS NOT NULL</TT
> restrictions to use indexes (Tom Lane)
      </P
><P
>       This is particularly useful for finding
       <CODE
CLASS="FUNCTION"
>MAX()</CODE
>/<CODE
CLASS="FUNCTION"
>MIN()</CODE
> values in indexes that
       contain many null values.
      </P
></LI
><LI
><P
>       Improve the optimizer's choices about when to use materialize nodes,
       and when to use sorting versus hashing for <TT
CLASS="LITERAL"
>DISTINCT</TT
>
       (Tom Lane)
      </P
></LI
><LI
><P
>       Improve the optimizer's equivalence detection for expressions involving
       <TT
CLASS="TYPE"
>boolean</TT
> <TT
CLASS="LITERAL"
>&lt;&gt;</TT
> operators (Tom Lane)
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109176"
>E.10.3.1.4. <A
HREF="geqo.html"
>GEQO</A
></A
></H4
><P
></P
><UL
><LI
><P
>       Use the same random seed every time GEQO plans a query (Andres
       Freund)
      </P
><P
>       While the Genetic Query Optimizer (GEQO) still selects
       random plans, it now always selects the same random plans for identical
       queries, thus giving more consistent performance. You can modify <A
HREF="runtime-config-query.html#GUC-GEQO-SEED"
><TT
CLASS="VARNAME"
>geqo_seed</TT
></A
> to experiment with
       alternative plans.
      </P
></LI
><LI
><P
>       Improve GEQO plan selection (Tom Lane)
      </P
><P
>       This avoids the rare error <SPAN
CLASS="QUOTE"
>"failed to make a valid plan"</SPAN
>,
       and should also improve planning speed.
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109189"
>E.10.3.1.5. Optimizer Statistics</A
></H4
><P
></P
><UL
><LI
><P
>       Improve <A
HREF="sql-analyze.html"
><TT
CLASS="COMMAND"
>ANALYZE</TT
></A
>
       to support inheritance-tree statistics (Tom Lane)
      </P
><P
>       This is particularly useful for partitioned tables.  However,
       autovacuum does not yet automatically re-analyze parent tables
       when child tables change.
      </P
></LI
><LI
><P
>       Improve <A
HREF="routine-vacuuming.html"
>autovacuum</A
>'s
       detection of when re-analyze is necessary (Tom Lane)
      </P
></LI
><LI
><P
>       Improve optimizer's estimation for greater/less-than comparisons
       (Tom Lane)
      </P
><P
>       When looking up statistics for greater/less-than comparisons,
       if the comparison value is in the first or last histogram bucket,
       use an index (if available) to fetch the current actual column
       minimum or maximum.  This greatly improves the accuracy of estimates
       for comparison values near the ends of the data range, particularly
       if the range is constantly changing due to addition of new data.
      </P
></LI
><LI
><P
>       Allow setting of number-of-distinct-values statistics using <A
HREF="sql-altertable.html"
><TT
CLASS="COMMAND"
>ALTER TABLE</TT
></A
>
       (Robert Haas)
      </P
><P
>       This allows users to override the estimated number or percentage of
       distinct values for a column. This statistic is normally computed by
       <TT
CLASS="COMMAND"
>ANALYZE</TT
>, but the estimate can be poor, especially on tables
       with very large numbers of rows.
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109209"
>E.10.3.1.6. Authentication</A
></H4
><P
></P
><UL
><LI
><P
>       Add support for <A
HREF="auth-methods.html#AUTH-RADIUS"
><ACRONYM
CLASS="ACRONYM"
>RADIUS</ACRONYM
></A
> (Remote
       Authentication Dial In User Service) authentication
       (Magnus Hagander)
      </P
></LI
><LI
><P
>       Allow <A
HREF="auth-methods.html#AUTH-LDAP"
><ACRONYM
CLASS="ACRONYM"
>LDAP</ACRONYM
></A
>
       (Lightweight Directory Access Protocol) authentication
       to operate in <SPAN
CLASS="QUOTE"
>"search/bind"</SPAN
> mode
       (Robert Fleming, Magnus Hagander)
      </P
><P
>       This allows the user to be looked up first, then the system uses
       the <ACRONYM
CLASS="ACRONYM"
>DN</ACRONYM
> (Distinguished Name) returned for that user.
      </P
></LI
><LI
><P
>       Add <A
HREF="auth-pg-hba-conf.html"
><TT
CLASS="LITERAL"
>samehost</TT
></A
>
       and <TT
CLASS="LITERAL"
>samenet</TT
> designations to
       <TT
CLASS="FILENAME"
>pg_hba.conf</TT
> (Stef Walter)
      </P
><P
>       These match the server's <ACRONYM
CLASS="ACRONYM"
>IP</ACRONYM
> address and subnet address
       respectively.
      </P
></LI
><LI
><P
>       Pass trusted SSL root certificate names to the client so the client
       can return an appropriate client certificate (Craig Ringer)
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109233"
>E.10.3.1.7. Monitoring</A
></H4
><P
></P
><UL
><LI
><P
>       Add the ability for clients to set an <A
HREF="libpq-connect.html#LIBPQ-CONNECT-APPLICATION-NAME"
>application
       name</A
>, which is displayed in
       <TT
CLASS="STRUCTNAME"
>pg_stat_activity</TT
> (Dave Page)
      </P
><P
>       This allows administrators to characterize database traffic
       and troubleshoot problems by source application.
      </P
></LI
><LI
><P
>       Add a SQLSTATE option (<TT
CLASS="LITERAL"
>%e</TT
>) to <A
HREF="runtime-config-logging.html#GUC-LOG-LINE-PREFIX"
><TT
CLASS="VARNAME"
>log_line_prefix</TT
></A
>
       (Guillaume Smet)
      </P
><P
>       This allows users to compile statistics on errors and messages
       by error code number.
      </P
></LI
><LI
><P
>       Write to the Windows event log in <ACRONYM
CLASS="ACRONYM"
>UTF16</ACRONYM
> encoding
       (Itagaki Takahiro)
      </P
><P
>       Now there is true multilingual support for PostgreSQL log messages
       on Windows.
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109251"
>E.10.3.1.8. Statistics Counters</A
></H4
><P
></P
><UL
><LI
><P
>       Add <A
HREF="monitoring-stats.html#MONITORING-STATS-FUNCS-TABLE"
><CODE
CLASS="FUNCTION"
>pg_stat_reset_shared('bgwriter')</CODE
></A
>
       to reset the cluster-wide shared statistics for the
       background writer (Greg Smith)
      </P
></LI
><LI
><P
>       Add <A
HREF="monitoring-stats.html#MONITORING-STATS-FUNCS-TABLE"
><CODE
CLASS="FUNCTION"
>pg_stat_reset_single_table_counters()</CODE
></A
>
       and <CODE
CLASS="FUNCTION"
>pg_stat_reset_single_function_counters()</CODE
>
       to allow resetting the statistics counters for individual
       tables and functions (Magnus Hagander)
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109263"
>E.10.3.1.9. Server Settings</A
></H4
><P
></P
><UL
><LI
><P
>       Allow setting of configuration parameters based on <A
HREF="sql-alterrole.html"
>database/role combinations</A
>
       (Alvaro Herrera)
      </P
><P
>       Previously only per-database and per-role settings were possible,
       not combinations. All role and database settings are now stored
       in the new <TT
CLASS="STRUCTNAME"
>pg_db_role_setting</TT
> system catalog. A new
       <SPAN
CLASS="APPLICATION"
>psql</SPAN
> command <TT
CLASS="LITERAL"
>\drds</TT
> shows these settings.
       The legacy system views <TT
CLASS="STRUCTNAME"
>pg_roles</TT
>,
       <TT
CLASS="STRUCTNAME"
>pg_shadow</TT
>, and <TT
CLASS="STRUCTNAME"
>pg_user</TT
>
       do not show combination settings, and therefore no longer
       completely represent the configuration for a user or database.
      </P
></LI
><LI
><P
>       Add server parameter <A
HREF="runtime-config-connection.html#GUC-BONJOUR"
><TT
CLASS="VARNAME"
>bonjour</TT
></A
>, which
       controls whether a Bonjour-enabled server advertises
       itself via <SPAN
CLASS="PRODUCTNAME"
>Bonjour</SPAN
> (Tom Lane)
      </P
><P
>       The default is off, meaning it does not advertise.  This allows
       packagers to distribute Bonjour-enabled builds without worrying
       that individual users might not want the feature.
      </P
></LI
><LI
><P
>       Add server parameter <A
HREF="runtime-config-query.html#GUC-ENABLE-MATERIAL"
><TT
CLASS="VARNAME"
>enable_material</TT
></A
>, which
       controls the use of materialize nodes in the optimizer
       (Robert Haas)
      </P
><P
>       The default is on.  When off, the optimizer will not add
       materialize nodes purely for performance reasons, though they
       will still be used when necessary for correctness.
      </P
></LI
><LI
><P
>       Change server parameter <A
HREF="runtime-config-logging.html#GUC-LOG-TEMP-FILES"
><TT
CLASS="VARNAME"
>log_temp_files</TT
></A
> to
       use default file size units of kilobytes (Robert Haas)
      </P
><P
>       Previously this setting was interpreted in bytes if no units were
       specified.
      </P
></LI
><LI
><P
>       Log changes of parameter values when <TT
CLASS="FILENAME"
>postgresql.conf</TT
> is
       reloaded (Peter Eisentraut)
      </P
><P
>       This lets administrators and security staff audit changes of database
       settings, and is also very convenient for checking the effects of
       <TT
CLASS="FILENAME"
>postgresql.conf</TT
> edits.
      </P
></LI
><LI
><P
>       Properly enforce superuser permissions for custom server parameters
       (Tom Lane)
      </P
><P
>       Non-superusers can no longer issue <TT
CLASS="COMMAND"
>ALTER
       ROLE</TT
>/<TT
CLASS="COMMAND"
>DATABASE SET</TT
> for parameters that are not currently
       known to the server.  This allows the server to correctly check that
       superuser-only parameters are only set by superusers.  Previously,
       the <TT
CLASS="LITERAL"
>SET</TT
> would be allowed and then ignored at session start,
       making superuser-only custom parameters much less useful than they
       should be.
      </P
></LI
></UL
></DIV
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN109303"
>E.10.3.2. Queries</A
></H3
><P
></P
><UL
><LI
><P
>      Perform <A
HREF="sql-select.html#SQL-FOR-UPDATE-SHARE"
><TT
CLASS="COMMAND"
>SELECT
      FOR UPDATE</TT
>/<TT
CLASS="LITERAL"
>SHARE</TT
></A
> processing after
      applying <TT
CLASS="LITERAL"
>LIMIT</TT
>, so the number of rows returned
      is always predictable (Tom Lane)
     </P
><P
>      Previously, changes made by concurrent transactions could cause a
      <TT
CLASS="COMMAND"
>SELECT FOR UPDATE</TT
> to unexpectedly return fewer rows than
      specified by its <TT
CLASS="LITERAL"
>LIMIT</TT
>. <TT
CLASS="LITERAL"
>FOR UPDATE</TT
> in combination
      with <TT
CLASS="LITERAL"
>ORDER BY</TT
> can still produce surprising results, but that
      can be corrected by placing <TT
CLASS="LITERAL"
>FOR UPDATE</TT
> in a subquery.
     </P
></LI
><LI
><P
>      Allow mixing of traditional and SQL-standard <A
HREF="sql-select.html#SQL-LIMIT"
><TT
CLASS="LITERAL"
>LIMIT</TT
>/<TT
CLASS="LITERAL"
>OFFSET</TT
></A
>
      syntax (Tom Lane)
     </P
></LI
><LI
><P
>      Extend the supported frame options in <A
HREF="sql-select.html#SQL-WINDOW"
>window functions</A
> (Hitoshi
      Harada)
     </P
><P
>      Frames can now start with <TT
CLASS="LITERAL"
>CURRENT ROW</TT
>, and the <TT
CLASS="LITERAL"
>ROWS
      <TT
CLASS="REPLACEABLE"
><I
>n</I
></TT
> PRECEDING</TT
>/<TT
CLASS="LITERAL"
>FOLLOWING</TT
> options are now
      supported.
     </P
></LI
><LI
><P
>      Make <TT
CLASS="COMMAND"
>SELECT INTO</TT
> and <TT
CLASS="COMMAND"
>CREATE TABLE AS</TT
> return
      row counts to the client in their command tags
      (Boszormenyi Zoltan)
     </P
><P
>      This can save an entire round-trip to the client, allowing result counts
      and pagination to be calculated without an additional
      <TT
CLASS="COMMAND"
>COUNT</TT
> query.
     </P
></LI
></UL
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109337"
>E.10.3.2.1. Unicode Strings</A
></H4
><P
></P
><UL
><LI
><P
>       Support Unicode surrogate pairs (dual 16-bit representation) in
       <A
HREF="sql-syntax-lexical.html#SQL-SYNTAX-STRINGS-UESCAPE"
><TT
CLASS="LITERAL"
>U&amp;</TT
></A
>
       strings and identifiers (Peter Eisentraut)
      </P
></LI
><LI
><P
>       Support Unicode escapes in <A
HREF="sql-syntax-lexical.html#SQL-SYNTAX-STRINGS-ESCAPE"
><TT
CLASS="LITERAL"
>E'...'</TT
></A
>
       strings (Marko Kreen)
      </P
></LI
></UL
></DIV
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN109348"
>E.10.3.3. Object Manipulation</A
></H3
><P
></P
><UL
><LI
><P
>      Speed up <A
HREF="sql-createdatabase.html"
><TT
CLASS="COMMAND"
>CREATE
      DATABASE</TT
></A
> by deferring flushes to disk (Andres
      Freund, Greg Stark)
     </P
></LI
><LI
><P
>      Allow <A
HREF="sql-comment.html"
>comments</A
> on
      columns of tables, views, and composite types only, not other
      relation types such as indexes and <ACRONYM
CLASS="ACRONYM"
>TOAST</ACRONYM
> tables (Tom Lane)
     </P
></LI
><LI
><P
>      Allow the creation of <A
HREF="sql-createtype.html#SQL-CREATETYPE-ENUM"
>enumerated types</A
> containing
      no values (Bruce Momjian)
     </P
></LI
><LI
><P
>      Let values of columns having storage type <TT
CLASS="LITERAL"
>MAIN</TT
> remain on
      the main heap page unless the row cannot fit on a page (Kevin Grittner)
     </P
><P
>      Previously <TT
CLASS="LITERAL"
>MAIN</TT
> values were forced out to <ACRONYM
CLASS="ACRONYM"
>TOAST</ACRONYM
>
      tables until the row size was less than one-quarter of the page size.
     </P
></LI
></UL
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109368"
>E.10.3.3.1. <TT
CLASS="COMMAND"
>ALTER TABLE</TT
></A
></H4
><P
></P
><UL
><LI
><P
>       Implement <TT
CLASS="LITERAL"
>IF EXISTS</TT
> for <TT
CLASS="LITERAL"
>ALTER TABLE DROP COLUMN</TT
>
       and <TT
CLASS="LITERAL"
>ALTER TABLE DROP CONSTRAINT </TT
> (Andres Freund)
      </P
></LI
><LI
><P
>       Allow <TT
CLASS="COMMAND"
>ALTER TABLE</TT
> commands that rewrite tables to skip
       <ACRONYM
CLASS="ACRONYM"
>WAL</ACRONYM
> logging (Itagaki Takahiro)
      </P
><P
>       Such operations either produce a new copy of the table or are rolled
       back, so <ACRONYM
CLASS="ACRONYM"
>WAL</ACRONYM
> archiving can be skipped, unless running in
       continuous archiving mode.  This reduces I/O overhead and improves
       performance.
      </P
></LI
><LI
><P
>       Fix failure of <TT
CLASS="LITERAL"
>ALTER TABLE <TT
CLASS="REPLACEABLE"
><I
>table</I
></TT
> ADD COLUMN
       <TT
CLASS="REPLACEABLE"
><I
>col</I
></TT
> serial</TT
> when done by non-owner of table
       (Tom Lane)
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109388"
>E.10.3.3.2. <A
HREF="sql-createtable.html"
><TT
CLASS="COMMAND"
>CREATE TABLE</TT
></A
></A
></H4
><P
></P
><UL
><LI
><P
>       Add support for copying <TT
CLASS="LITERAL"
>COMMENTS</TT
> and <TT
CLASS="LITERAL"
>STORAGE</TT
>
       settings in <TT
CLASS="COMMAND"
>CREATE TABLE ... LIKE</TT
> commands
       (Itagaki Takahiro)
      </P
></LI
><LI
><P
>       Add a shortcut for copying all properties in <TT
CLASS="COMMAND"
>CREATE
       TABLE ... LIKE</TT
> commands (Itagaki Takahiro)
      </P
></LI
><LI
><P
>       Add the SQL-standard
       <TT
CLASS="LITERAL"
>CREATE TABLE ... OF <TT
CLASS="REPLACEABLE"
><I
>type</I
></TT
></TT
> command
       (Peter Eisentraut)
      </P
><P
>       This allows creation of a table that matches an existing composite
       type. Additional constraints and defaults can be specified in the
       command.
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109406"
>E.10.3.3.3. Constraints</A
></H4
><P
></P
><UL
><LI
><P
>       Add <A
HREF="sql-createtable.html#SQL-CREATETABLE-COMPATIBILITY"
>deferrable
       unique constraints</A
> (Dean Rasheed)
      </P
><P
>       This allows mass updates, such as
       <TT
CLASS="LITERAL"
>UPDATE tab SET col = col + 1</TT
>,
       to work reliably
       on columns that have unique indexes or are marked as primary keys.
       If the constraint is specified as <TT
CLASS="LITERAL"
>DEFERRABLE</TT
> it will be
       checked at the end of the statement, rather than after each row is
       updated. The constraint check can also be deferred until the end of the
       current transaction, allowing such updates to be spread over multiple
       SQL commands.
      </P
></LI
><LI
><P
>       Add
       <A
HREF="ddl-constraints.html#DDL-CONSTRAINTS-EXCLUSION"
>exclusion constraints</A
>
       (Jeff Davis)
      </P
><P
>       Exclusion constraints generalize uniqueness constraints by allowing
       arbitrary comparison operators, not just equality.  They are created
       with the <A
HREF="sql-createtable.html#SQL-CREATETABLE-EXCLUDE"
><TT
CLASS="COMMAND"
>CREATE
       TABLE CONSTRAINT ... EXCLUDE</TT
></A
> clause.
       The most common use of exclusion constraints is to specify that column
       entries must not overlap, rather than simply not be equal.  This is
       useful for time periods and other ranges, as well as arrays.
       This feature enhances checking of data integrity for many
       calendaring, time-management, and scientific applications.
      </P
></LI
><LI
><P
>       Improve uniqueness-constraint violation error messages to
       report the values causing the failure (Itagaki Takahiro)
      </P
><P
>       For example, a uniqueness constraint violation might now report
       <TT
CLASS="LITERAL"
>Key (x)=(2) already exists</TT
>.
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109425"
>E.10.3.3.4. Object Permissions</A
></H4
><P
></P
><UL
><LI
><P
>       Add the ability to make mass permission changes across a whole
       schema using the new <A
HREF="sql-grant.html"
><TT
CLASS="COMMAND"
>GRANT</TT
>/<TT
CLASS="COMMAND"
>REVOKE
       IN SCHEMA</TT
></A
> clause (Petr Jelinek)
      </P
><P
>       This simplifies management of object permissions
       and makes it easier to utilize database roles for application
       data security.
      </P
></LI
><LI
><P
>       Add <A
HREF="sql-alterdefaultprivileges.html"
><TT
CLASS="COMMAND"
>ALTER
       DEFAULT PRIVILEGES</TT
></A
> command to control privileges
       of objects created later (Petr Jelinek)
      </P
><P
>       This greatly simplifies the assignment of object privileges in a
       complex database application.  Default privileges can be set for
       tables, views, sequences, and functions. Defaults may be assigned on a
       per-schema basis, or database-wide.
      </P
></LI
><LI
><P
>       Add the ability to control large object (BLOB) permissions with
       <TT
CLASS="COMMAND"
>GRANT</TT
>/<TT
CLASS="COMMAND"
>REVOKE</TT
> (KaiGai Kohei)
      </P
><P
>       Formerly, any database user could read or modify any large object.
       Read and write permissions can now be granted and revoked per
       large object, and the ownership of large objects is tracked.
      </P
></LI
></UL
></DIV
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN109444"
>E.10.3.4. Utility Operations</A
></H3
><P
></P
><UL
><LI
><P
>      Make <A
HREF="sql-listen.html"
><TT
CLASS="COMMAND"
>LISTEN</TT
></A
>/<A
HREF="sql-notify.html"
><TT
CLASS="COMMAND"
>NOTIFY</TT
></A
> store pending events
      in a memory queue, rather than in a system table (Joachim
      Wieland)
     </P
><P
>      This substantially improves performance, while retaining the existing
      features of transactional support and guaranteed delivery.
     </P
></LI
><LI
><P
>      Allow <A
HREF="sql-notify.html"
><TT
CLASS="COMMAND"
>NOTIFY</TT
></A
>
      to pass an optional <SPAN
CLASS="QUOTE"
>"payload"</SPAN
> string to listeners
      (Joachim Wieland)
     </P
><P
>      This greatly improves the usefulness of
      <TT
CLASS="COMMAND"
>LISTEN</TT
>/<TT
CLASS="COMMAND"
>NOTIFY</TT
> as a
      general-purpose event queue system.
     </P
></LI
><LI
><P
>      Allow <A
HREF="sql-cluster.html"
><TT
CLASS="COMMAND"
>CLUSTER</TT
></A
>
      on all per-database system catalogs (Tom Lane)
     </P
><P
>      Shared catalogs still cannot be clustered.
     </P
></LI
></UL
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109467"
>E.10.3.4.1. <A
HREF="sql-copy.html"
><TT
CLASS="COMMAND"
>COPY</TT
></A
></A
></H4
><P
></P
><UL
><LI
><P
>       Accept <TT
CLASS="LITERAL"
>COPY ... CSV FORCE QUOTE *</TT
>
       (Itagaki Takahiro)
      </P
><P
>       Now <TT
CLASS="LITERAL"
>*</TT
> can be used as shorthand for <SPAN
CLASS="QUOTE"
>"all columns"</SPAN
>
       in the <TT
CLASS="LITERAL"
>FORCE QUOTE</TT
> clause.
      </P
></LI
><LI
><P
>       Add new <TT
CLASS="COMMAND"
>COPY</TT
> syntax that allows options to be
       specified inside parentheses (Robert Haas, Emmanuel Cecchet)
      </P
><P
>       This allows greater flexibility for future <TT
CLASS="COMMAND"
>COPY</TT
> options.
       The old syntax is still supported, but only for pre-existing options.
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109484"
>E.10.3.4.2. <A
HREF="sql-explain.html"
><TT
CLASS="COMMAND"
>EXPLAIN</TT
></A
></A
></H4
><P
></P
><UL
><LI
><P
>       Allow <TT
CLASS="COMMAND"
>EXPLAIN</TT
> to output in <ACRONYM
CLASS="ACRONYM"
>XML</ACRONYM
>,
       <ACRONYM
CLASS="ACRONYM"
>JSON</ACRONYM
>, or <ACRONYM
CLASS="ACRONYM"
>YAML</ACRONYM
> format (Robert Haas, Greg
       Sabino Mullane)
      </P
><P
>       The new output formats are easily machine-readable, supporting the
       development of new tools for analysis of <TT
CLASS="COMMAND"
>EXPLAIN</TT
> output.
      </P
></LI
><LI
><P
>       Add new <TT
CLASS="LITERAL"
>BUFFERS</TT
> option to report query
       buffer usage during <TT
CLASS="COMMAND"
>EXPLAIN ANALYZE</TT
> (Itagaki Takahiro)
      </P
><P
>       This allows better query profiling for individual queries.
       Buffer usage is no longer reported in the output for <A
HREF="runtime-config-statistics.html#RUNTIME-CONFIG-STATISTICS-MONITOR"
>log_statement_stats</A
>
       and related settings.
      </P
></LI
><LI
><P
>       Add hash usage information to <TT
CLASS="COMMAND"
>EXPLAIN</TT
> output (Robert
       Haas)
      </P
></LI
><LI
><P
>       Add new <TT
CLASS="COMMAND"
>EXPLAIN</TT
> syntax that allows options to be
       specified inside parentheses (Robert Haas)
      </P
><P
>       This allows greater flexibility for future <TT
CLASS="COMMAND"
>EXPLAIN</TT
> options.
       The old syntax is still supported, but only for pre-existing options.
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109511"
>E.10.3.4.3. <A
HREF="sql-vacuum.html"
><TT
CLASS="COMMAND"
>VACUUM</TT
></A
></A
></H4
><P
></P
><UL
><LI
><P
>       Change <TT
CLASS="COMMAND"
>VACUUM FULL</TT
> to rewrite the entire table and
       rebuild its indexes, rather than moving individual rows around to
       compact space (Itagaki Takahiro, Tom Lane)
      </P
><P
>       The previous method was usually slower and caused index bloat.
       Note that the new method will use more disk space transiently
       during <TT
CLASS="COMMAND"
>VACUUM FULL</TT
>; potentially as much as twice
       the space normally occupied by the table and its indexes.
      </P
></LI
><LI
><P
>       Add new <TT
CLASS="COMMAND"
>VACUUM</TT
> syntax that allows options to be
       specified inside parentheses (Itagaki Takahiro)
      </P
><P
>       This allows greater flexibility for future <TT
CLASS="COMMAND"
>VACUUM</TT
> options.
       The old syntax is still supported, but only for pre-existing options.
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109526"
>E.10.3.4.4. Indexes</A
></H4
><P
></P
><UL
><LI
><P
>       Allow an index to be named automatically by omitting the index name in
       <A
HREF="sql-createindex.html"
><TT
CLASS="COMMAND"
>CREATE INDEX</TT
></A
>
       (Tom Lane)
      </P
></LI
><LI
><P
>       By default, multicolumn indexes are now named after all their columns;
       and index expression columns are now named based on their expressions
       (Tom Lane)
      </P
></LI
><LI
><P
>       Reindexing shared system catalogs is now fully transactional
       and crash-safe (Tom Lane)
      </P
><P
>       Formerly, reindexing a shared index was only allowed in standalone
       mode, and a crash during the operation could leave the index in
       worse condition than it was before.
      </P
></LI
><LI
><P
>       Add <TT
CLASS="LITERAL"
>point_ops</TT
> operator class for <ACRONYM
CLASS="ACRONYM"
>GiST</ACRONYM
>
      (Teodor Sigaev)
      </P
><P
>       This feature permits <ACRONYM
CLASS="ACRONYM"
>GiST</ACRONYM
> indexing of <TT
CLASS="TYPE"
>point</TT
>
       columns.  The index can be used for several types of queries
       such as <TT
CLASS="REPLACEABLE"
><I
>point</I
></TT
> <TT
CLASS="LITERAL"
>&lt;@</TT
> <TT
CLASS="REPLACEABLE"
><I
>polygon</I
></TT
>
       (point is in polygon).  This should make many
       <SPAN
CLASS="PRODUCTNAME"
>PostGIS</SPAN
> queries faster.
      </P
></LI
><LI
><P
>       Use red-black binary trees for <ACRONYM
CLASS="ACRONYM"
>GIN</ACRONYM
> index creation
       (Teodor Sigaev)
      </P
><P
>       Red-black trees are self-balancing.  This avoids slowdowns in
       cases where the input is in nonrandom order.
      </P
></LI
></UL
></DIV
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN109553"
>E.10.3.5. Data Types</A
></H3
><P
></P
><UL
><LI
><P
>      Allow <A
HREF="datatype-binary.html"
><TT
CLASS="TYPE"
>bytea</TT
></A
> values
      to be written in hex notation (Peter Eisentraut)
     </P
><P
>      The server parameter <A
HREF="runtime-config-client.html#GUC-BYTEA-OUTPUT"
><TT
CLASS="VARNAME"
>bytea_output</TT
></A
> controls
      whether hex or traditional format is used for <TT
CLASS="TYPE"
>bytea</TT
>
      output.  Libpq's <CODE
CLASS="FUNCTION"
>PQescapeByteaConn()</CODE
> function automatically
      uses the hex format when connected to <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> 9.0
      or newer servers.  However, pre-9.0 libpq versions will not
      correctly process hex format from newer servers.
     </P
><P
>      The new hex format will be directly compatible with more applications
      that use binary data, allowing them to store and retrieve it without
      extra conversion.  It is also significantly faster to read and write
      than the traditional format.
     </P
></LI
><LI
><P
>      Allow server parameter <A
HREF="runtime-config-client.html#GUC-EXTRA-FLOAT-DIGITS"
>extra_float_digits</A
>
      to be increased to <TT
CLASS="LITERAL"
>3</TT
> (Tom Lane)
     </P
><P
>      The previous maximum <TT
CLASS="VARNAME"
>extra_float_digits</TT
> setting was
      <TT
CLASS="LITERAL"
>2</TT
>.  There are cases where 3 digits are needed to dump and
      restore <TT
CLASS="TYPE"
>float4</TT
> values exactly.  <SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
> will
      now use the setting of 3 when dumping from a server that allows it.
     </P
></LI
><LI
><P
>      Tighten input checking for <TT
CLASS="TYPE"
>int2vector</TT
> values (Caleb
      Welton)
     </P
></LI
></UL
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109579"
>E.10.3.5.1. <A
HREF="textsearch.html"
>Full Text Search</A
></A
></H4
><P
></P
><UL
><LI
><P
>       Add prefix support in <TT
CLASS="LITERAL"
>synonym</TT
> dictionaries
       (Teodor Sigaev)
      </P
></LI
><LI
><P
>       Add <I
CLASS="FIRSTTERM"
>filtering</I
> dictionaries (Teodor Sigaev)
      </P
><P
>       Filtering dictionaries allow tokens to be modified then passed to
       subsequent dictionaries.
      </P
></LI
><LI
><P
>       Allow underscores in email-address tokens (Teodor Sigaev)
      </P
></LI
><LI
><P
>       Use more standards-compliant rules for parsing <ACRONYM
CLASS="ACRONYM"
>URL</ACRONYM
> tokens
       (Tom Lane)
      </P
></LI
></UL
></DIV
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN109595"
>E.10.3.6. Functions</A
></H3
><P
></P
><UL
><LI
><P
>      Allow function calls to supply parameter names and match them to named
      parameters in the function definition (Pavel Stehule)
     </P
><P
>      For example, if a function is defined to take parameters <TT
CLASS="LITERAL"
>a</TT
>
      and <TT
CLASS="LITERAL"
>b</TT
>, it can be called with <TT
CLASS="LITERAL"
>func(a := 7, b
      := 12)</TT
> or <TT
CLASS="LITERAL"
>func(b := 12, a := 7)</TT
>.
     </P
></LI
><LI
><P
>      Support locale-specific <A
HREF="functions-matching.html#FUNCTIONS-POSIX-REGEXP"
>regular expression</A
>
      processing with <ACRONYM
CLASS="ACRONYM"
>UTF-8</ACRONYM
> server encoding (Tom Lane)
     </P
><P
>      Locale-specific regular expression functionality includes
      case-insensitive matching and locale-specific character classes.
      Previously, these features worked correctly for non-<ACRONYM
CLASS="ACRONYM"
>ASCII</ACRONYM
>
      characters only if the database used a single-byte server encoding (such
      as LATIN1).  They will still misbehave in multi-byte encodings other
      than <ACRONYM
CLASS="ACRONYM"
>UTF-8</ACRONYM
>.
     </P
></LI
><LI
><P
>      Add support for scientific notation in <A
HREF="functions-formatting.html"
><CODE
CLASS="FUNCTION"
>to_char()</CODE
></A
>
      (<A
HREF="functions-formatting.html#FUNCTIONS-FORMATTING-NUMERIC-TABLE"
><TT
CLASS="LITERAL"
>EEEE</TT
>
      specification</A
>)
      (Pavel Stehule, Brendan Jurd)
     </P
></LI
><LI
><P
>      Make <CODE
CLASS="FUNCTION"
>to_char()</CODE
> honor <A
HREF="functions-formatting.html#FUNCTIONS-FORMATTING-DATETIMEMOD-TABLE"
><TT
CLASS="LITERAL"
>FM</TT
></A
>
      (fill mode) in <TT
CLASS="LITERAL"
>Y</TT
>, <TT
CLASS="LITERAL"
>YY</TT
>, and
      <TT
CLASS="LITERAL"
>YYY</TT
> specifications (Bruce Momjian, Tom Lane)
     </P
><P
>      It was already honored by <TT
CLASS="LITERAL"
>YYYY</TT
>.
     </P
></LI
><LI
><P
>      Fix <CODE
CLASS="FUNCTION"
>to_char()</CODE
> to output localized numeric and monetary
      strings in the correct encoding on <SPAN
CLASS="PRODUCTNAME"
>Windows</SPAN
>
      (Hiroshi Inoue, Itagaki Takahiro, Bruce Momjian)
     </P
></LI
><LI
><P
>      Correct calculations of <A
HREF="functions-geometry.html#FUNCTIONS-GEOMETRY-OP-TABLE"
><SPAN
CLASS="QUOTE"
>"overlaps"</SPAN
></A
>
      and <SPAN
CLASS="QUOTE"
>"contains"</SPAN
> operations for polygons (Teodor Sigaev)
     </P
><P
>      The polygon <TT
CLASS="LITERAL"
>&amp;&amp;</TT
> (overlaps) operator formerly just
      checked to see if the two polygons' bounding boxes overlapped.  It now
      does a more correct check.  The polygon <TT
CLASS="LITERAL"
>@&gt;</TT
> and
      <TT
CLASS="LITERAL"
>&lt;@</TT
> (contains/contained by) operators formerly checked
      to see if one polygon's vertexes were all contained in the other;
      this can wrongly report <SPAN
CLASS="QUOTE"
>"true"</SPAN
> for some non-convex polygons.
      Now they check that all line segments of one polygon are contained in
      the other.
     </P
></LI
></UL
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109642"
>E.10.3.6.1. Aggregates</A
></H4
><P
></P
><UL
><LI
><P
>       Allow aggregate functions to use <A
HREF="sql-expressions.html#SYNTAX-AGGREGATES"
><TT
CLASS="LITERAL"
>ORDER BY</TT
></A
> (Andrew Gierth)
      </P
><P
>       For example, this is now supported: <TT
CLASS="LITERAL"
>array_agg(a ORDER BY
       b)</TT
>.  This is useful with aggregates for which the order of input
       values is significant, and eliminates the need to use a nonstandard
       subquery to determine the ordering.
      </P
></LI
><LI
><P
>       Multi-argument aggregate functions can now use <TT
CLASS="LITERAL"
>DISTINCT</TT
>
       (Andrew Gierth)
      </P
></LI
><LI
><P
>       Add the <A
HREF="functions-aggregate.html#FUNCTIONS-AGGREGATE-TABLE"
><CODE
CLASS="FUNCTION"
>string_agg()</CODE
></A
>
       aggregate function to combine values into a single
       string (Pavel Stehule)
      </P
></LI
><LI
><P
>       Aggregate functions that are called with <TT
CLASS="LITERAL"
>DISTINCT</TT
> are
       now passed NULL values if the aggregate transition function is
       not marked as <TT
CLASS="LITERAL"
>STRICT</TT
> (Andrew Gierth)
      </P
><P
>       For example, <TT
CLASS="LITERAL"
>agg(DISTINCT x)</TT
> might pass a NULL <TT
CLASS="LITERAL"
>x</TT
>
       value to <CODE
CLASS="FUNCTION"
>agg()</CODE
>.  This is more consistent with the behavior
       in non-<TT
CLASS="LITERAL"
>DISTINCT</TT
> cases.
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109667"
>E.10.3.6.2. Bit Strings</A
></H4
><P
></P
><UL
><LI
><P
>       Add <A
HREF="functions-binarystring.html#FUNCTIONS-BINARYSTRING-OTHER"
><CODE
CLASS="FUNCTION"
>get_bit()</CODE
></A
>
       and <CODE
CLASS="FUNCTION"
>set_bit()</CODE
> functions for <TT
CLASS="TYPE"
>bit</TT
>
       strings, mirroring those for <TT
CLASS="TYPE"
>bytea</TT
> (Leonardo
       F)
      </P
></LI
><LI
><P
>       Implement <A
HREF="functions-string.html#FUNCTIONS-STRING-SQL"
><CODE
CLASS="FUNCTION"
>OVERLAY()</CODE
></A
>
       (replace) for <TT
CLASS="TYPE"
>bit</TT
> strings and <TT
CLASS="TYPE"
>bytea</TT
>
       (Leonardo F)
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109683"
>E.10.3.6.3. Object Information Functions</A
></H4
><P
></P
><UL
><LI
><P
>       Add <A
HREF="functions-admin.html#FUNCTIONS-ADMIN-DBSIZE"
><CODE
CLASS="FUNCTION"
>pg_table_size()</CODE
></A
>
       and <CODE
CLASS="FUNCTION"
>pg_indexes_size()</CODE
> to provide a more
       user-friendly interface to the <CODE
CLASS="FUNCTION"
>pg_relation_size()</CODE
>
       function (Bernd Helmle)
      </P
></LI
><LI
><P
>       Add <A
HREF="functions-info.html#FUNCTIONS-INFO-ACCESS-TABLE"
><CODE
CLASS="FUNCTION"
>has_sequence_privilege()</CODE
></A
>
       for sequence permission checking (Abhijit Menon-Sen)
      </P
></LI
><LI
><P
>       Update the <A
HREF="information-schema.html"
>information_schema</A
>
       views to conform to SQL:2008
       (Peter Eisentraut)
      </P
></LI
><LI
><P
>       Make the <TT
CLASS="LITERAL"
>information_schema</TT
> views correctly display maximum
       octet lengths for <TT
CLASS="TYPE"
>char</TT
> and <TT
CLASS="TYPE"
>varchar</TT
> columns (Peter
       Eisentraut)
      </P
></LI
><LI
><P
>       Speed up <TT
CLASS="LITERAL"
>information_schema</TT
> privilege views
       (Joachim Wieland)
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109707"
>E.10.3.6.4. Function and Trigger Creation</A
></H4
><P
></P
><UL
><LI
><P
>       Support execution of anonymous code blocks using the <A
HREF="sql-do.html"
><TT
CLASS="COMMAND"
>DO</TT
></A
> statement
       (Petr Jelinek, Joshua Tolley, Hannu Valtonen)
      </P
><P
>       This allows execution of server-side code without the need to create
       and delete a temporary function definition.  Code can be executed in
       any language for which the user has permissions to define a function.
      </P
></LI
><LI
><P
>       Implement SQL-standard-compliant <A
HREF="sql-createtrigger.html"
>per-column triggers</A
>
       (Itagaki Takahiro)
      </P
><P
>       Such triggers are fired only when the specified column(s) are affected
       by the query, e.g. appear in an <TT
CLASS="COMMAND"
>UPDATE</TT
>'s <TT
CLASS="LITERAL"
>SET</TT
>
       list.
      </P
></LI
><LI
><P
>       Add the <TT
CLASS="LITERAL"
>WHEN</TT
> clause to <A
HREF="sql-createtrigger.html"
><TT
CLASS="COMMAND"
>CREATE TRIGGER</TT
></A
>
       to allow control over whether a trigger is fired (Itagaki
       Takahiro)
      </P
><P
>       While the same type of check can always be performed inside the
       trigger, doing it in an external <TT
CLASS="LITERAL"
>WHEN</TT
> clause can have
       performance benefits.
      </P
></LI
></UL
></DIV
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN109728"
>E.10.3.7. Server-Side Languages</A
></H3
><P
></P
><UL
><LI
><P
>      Add the <TT
CLASS="LITERAL"
>OR REPLACE</TT
> clause to <A
HREF="sql-createlanguage.html"
><TT
CLASS="COMMAND"
>CREATE LANGUAGE</TT
></A
>
      (Tom Lane)
     </P
><P
>      This is helpful to optionally install a language if it does not
      already exist, and is particularly helpful now that PL/pgSQL is
      installed by default.
     </P
></LI
></UL
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109737"
>E.10.3.7.1. <A
HREF="plpgsql.html"
>PL/pgSQL</A
> Server-Side
    Language</A
></H4
><P
></P
><UL
><LI
><P
>       Install PL/pgSQL by default (Bruce Momjian)
      </P
><P
>       The language can still be removed from a particular database if the
       administrator has security or performance concerns about making it
       available.
      </P
></LI
><LI
><P
>       Improve handling of cases where PL/pgSQL variable names conflict with
       identifiers used in queries within a function
       (Tom Lane)
      </P
><P
>       The default behavior is now to throw an error when there is a conflict,
       so as to avoid surprising behaviors.  This can be modified, via the
       configuration parameter <A
HREF="plpgsql-implementation.html#PLPGSQL-VAR-SUBST"
><TT
CLASS="VARNAME"
>plpgsql.variable_conflict</TT
></A
>
       or the per-function option <TT
CLASS="LITERAL"
>#variable_conflict</TT
>, to allow
       either the variable or the query-supplied column to be used.  In any
       case PL/pgSQL will no longer attempt to substitute variables in places
       where they would not be syntactically valid.
      </P
></LI
><LI
><P
>       Make PL/pgSQL use the main lexer, rather than its own version
       (Tom Lane)
      </P
><P
>       This ensures accurate tracking of the main system's behavior for details
       such as string escaping.  Some user-visible details, such as the set
       of keywords considered reserved in PL/pgSQL, have changed in
       consequence.
      </P
></LI
><LI
><P
>       Avoid throwing an unnecessary error for an invalid record reference
       (Tom Lane)
      </P
><P
>       An error is now thrown only if the reference is actually fetched,
       rather than whenever the enclosing expression is reached.  For
       example, many people have tried to do this in triggers:
</P><PRE
CLASS="PROGRAMLISTING"
>if TG_OP = 'INSERT' and NEW.col1 = ... then</PRE
><P>
       This will now actually work as expected.
      </P
></LI
><LI
><P
>       Improve PL/pgSQL's ability to handle row types with dropped columns
       (Pavel Stehule)
      </P
></LI
><LI
><P
>       Allow input parameters to be assigned values within
       PL/pgSQL functions (Steve Prentice)
      </P
><P
>       Formerly, input parameters were treated as being declared
       <TT
CLASS="LITERAL"
>CONST</TT
>, so the function's code could not change their
       values.  This restriction has been removed to simplify
       porting of functions from other DBMSes that do not impose the
       equivalent restriction.  An input parameter now acts like a local
       variable initialized to the passed-in value.
      </P
></LI
><LI
><P
>       Improve error location reporting in PL/pgSQL (Tom Lane)
      </P
></LI
><LI
><P
>       Add <TT
CLASS="REPLACEABLE"
><I
>count</I
></TT
> and <TT
CLASS="LITERAL"
>ALL</TT
> options to <TT
CLASS="COMMAND"
>MOVE
       FORWARD</TT
>/<TT
CLASS="LITERAL"
>BACKWARD</TT
> in PL/pgSQL (Pavel Stehule)
      </P
></LI
><LI
><P
>       Allow PL/pgSQL's <TT
CLASS="LITERAL"
>WHERE CURRENT OF</TT
> to use a cursor
       variable (Tom Lane)
      </P
></LI
><LI
><P
>       Allow PL/pgSQL's <TT
CLASS="COMMAND"
>OPEN <TT
CLASS="REPLACEABLE"
><I
>cursor</I
></TT
> FOR EXECUTE</TT
> to
       use parameters (Pavel Stehule, Itagaki Takahiro)
      </P
><P
>       This is accomplished with a new <TT
CLASS="LITERAL"
>USING</TT
> clause.
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109780"
>E.10.3.7.2. <A
HREF="plperl.html"
>PL/Perl</A
> Server-Side Language</A
></H4
><P
></P
><UL
><LI
><P
>       Add new PL/Perl functions: <A
HREF="plperl-builtins.html#PLPERL-UTILITY-FUNCTIONS"
><CODE
CLASS="FUNCTION"
>quote_literal()</CODE
></A
>,
       <CODE
CLASS="FUNCTION"
>quote_nullable()</CODE
>, <CODE
CLASS="FUNCTION"
>quote_ident()</CODE
>,
       <CODE
CLASS="FUNCTION"
>encode_bytea()</CODE
>, <CODE
CLASS="FUNCTION"
>decode_bytea()</CODE
>,
       <CODE
CLASS="FUNCTION"
>looks_like_number()</CODE
>,
       <CODE
CLASS="FUNCTION"
>encode_array_literal()</CODE
>,
       <CODE
CLASS="FUNCTION"
>encode_array_constructor()</CODE
> (Tim Bunce)
      </P
></LI
><LI
><P
>       Add server parameter <A
HREF="plperl-under-the-hood.html#GUC-PLPERL-ON-INIT"
><TT
CLASS="VARNAME"
>plperl.on_init</TT
></A
> to
       specify a PL/Perl initialization function (Tim
       Bunce)
      </P
><P
>       <A
HREF="plperl-under-the-hood.html#GUC-PLPERL-ON-PLPERL-INIT"
><TT
CLASS="VARNAME"
>plperl.on_plperl_init</TT
></A
>
       and <A
HREF="plperl-under-the-hood.html#GUC-PLPERL-ON-PLPERL-INIT"
><TT
CLASS="VARNAME"
>plperl.on_plperlu_init</TT
></A
>
       are also available for initialization that is specific to the trusted
       or untrusted language respectively.
      </P
></LI
><LI
><P
>       Support <TT
CLASS="COMMAND"
>END</TT
> blocks in PL/Perl (Tim Bunce)
      </P
><P
>       <TT
CLASS="COMMAND"
>END</TT
> blocks do not currently allow database access.
      </P
></LI
><LI
><P
>       Allow <TT
CLASS="COMMAND"
>use strict</TT
> in PL/Perl (Tim Bunce)
      </P
><P
>       Perl <TT
CLASS="LITERAL"
>strict</TT
> checks can also be globally enabled with the
       new server parameter <A
HREF="plperl-under-the-hood.html#GUC-PLPERL-USE-STRICT"
><TT
CLASS="VARNAME"
>plperl.use_strict</TT
></A
>.
      </P
></LI
><LI
><P
>       Allow <TT
CLASS="COMMAND"
>require</TT
> in PL/Perl (Tim Bunce)
      </P
><P
>       This basically tests to see if the module is loaded, and if not,
       generates an error.  It will not allow loading of modules that
       the administrator has not preloaded via the initialization parameters.
      </P
></LI
><LI
><P
>       Allow <TT
CLASS="COMMAND"
>use feature</TT
> in PL/Perl if Perl version 5.10 or
       later is used (Tim Bunce)
      </P
></LI
><LI
><P
>       Verify that PL/Perl return values are valid in the server encoding
       (Andrew Dunstan)
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109825"
>E.10.3.7.3. <A
HREF="plpython.html"
>PL/Python</A
> Server-Side Language</A
></H4
><P
></P
><UL
><LI
><P
>       Add Unicode support in PL/Python (Peter Eisentraut)
      </P
><P
>       Strings are automatically converted from/to the server encoding as
       necessary.
      </P
></LI
><LI
><P
>       Improve <TT
CLASS="TYPE"
>bytea</TT
> support in PL/Python (Caleb Welton)
      </P
><P
>       <TT
CLASS="TYPE"
>Bytea</TT
> values passed into PL/Python are now represented as
       binary, rather than the PostgreSQL <TT
CLASS="TYPE"
>bytea</TT
> text format.
       <TT
CLASS="TYPE"
>Bytea</TT
> values containing null bytes are now also output
       properly from PL/Python.  Passing of boolean, integer, and float
       values was also improved.
      </P
></LI
><LI
><P
>       Support <A
HREF="plpython-data.html#PLPYTHON-ARRAYS"
>arrays</A
> as parameters and
       return values in PL/Python (Peter Eisentraut)
      </P
></LI
><LI
><P
>       Improve mapping of SQL domains to Python types (Peter Eisentraut)
      </P
></LI
><LI
><P
>       Add <SPAN
CLASS="APPLICATION"
>Python</SPAN
> 3 support to PL/Python (Peter Eisentraut)
      </P
><P
>       The new server-side language is called <A
HREF="plpython-python23.html"
><TT
CLASS="LITERAL"
>plpython3u</TT
></A
>.  This
       cannot be used in the same session with the
       <SPAN
CLASS="APPLICATION"
>Python</SPAN
> 2 server-side language.
      </P
></LI
><LI
><P
>       Improve error location and exception reporting in PL/Python (Peter Eisentraut)
      </P
></LI
></UL
></DIV
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN109853"
>E.10.3.8. Client Applications</A
></H3
><P
></P
><UL
><LI
><P
>     Add an <TT
CLASS="OPTION"
>--analyze-only</TT
> option to <A
HREF="app-vacuumdb.html"
><TT
CLASS="COMMAND"
>vacuumdb</TT
></A
>, to analyze without
     vacuuming (Bruce Momjian)
     </P
></LI
></UL
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109861"
>E.10.3.8.1. <A
HREF="app-psql.html"
><SPAN
CLASS="APPLICATION"
>psql</SPAN
></A
></A
></H4
><P
></P
><UL
><LI
><P
>       Add support for quoting/escaping the values of <SPAN
CLASS="APPLICATION"
>psql</SPAN
>
       <A
HREF="app-psql.html#APP-PSQL-VARIABLES"
>variables</A
> as SQL strings or
       identifiers (Pavel Stehule, Robert Haas)
      </P
><P
>       For example, <TT
CLASS="LITERAL"
>:'var'</TT
> will produce the value of
       <TT
CLASS="LITERAL"
>var</TT
> quoted and properly escaped as a literal string, while
       <TT
CLASS="LITERAL"
>:"var"</TT
> will produce its value quoted and escaped as an
       identifier.
      </P
></LI
><LI
><P
>       Ignore a leading UTF-8-encoded Unicode byte-order marker in
       script files read by <SPAN
CLASS="APPLICATION"
>psql</SPAN
> (Itagaki Takahiro)
      </P
><P
>       This is enabled when the client encoding is <ACRONYM
CLASS="ACRONYM"
>UTF-8</ACRONYM
>.
       It improves compatibility with certain editors, mostly on Windows,
       that insist on inserting such markers.
      </P
></LI
><LI
><P
>       Fix <TT
CLASS="COMMAND"
>psql --file -</TT
> to properly honor <A
HREF="app-psql.html#R1-APP-PSQL-3"
><TT
CLASS="OPTION"
>--single-transaction</TT
></A
>
       (Bruce Momjian)
      </P
></LI
><LI
><P
>       Avoid overwriting of <SPAN
CLASS="APPLICATION"
>psql</SPAN
>'s command-line history when
       two <SPAN
CLASS="APPLICATION"
>psql</SPAN
> sessions are run concurrently (Tom Lane)
      </P
></LI
><LI
><P
>       Improve <SPAN
CLASS="APPLICATION"
>psql</SPAN
>'s tab completion support (Itagaki
       Takahiro)
      </P
></LI
><LI
><P
>       Show <TT
CLASS="LITERAL"
>\timing</TT
> output when it is enabled, regardless of
       <SPAN
CLASS="QUOTE"
>"quiet"</SPAN
> mode (Peter Eisentraut)
      </P
></LI
></UL
><DIV
CLASS="SECT5"
><H5
CLASS="SECT5"
><A
NAME="AEN109895"
>E.10.3.8.1.1. <SPAN
CLASS="APPLICATION"
>psql</SPAN
> Display</A
></H5
><P
></P
><UL
><LI
><P
>        Improve display of wrapped columns in <SPAN
CLASS="APPLICATION"
>psql</SPAN
> (Roger
        Leigh)
       </P
><P
>        This behavior is now the default.
        The previous formatting is available by using <TT
CLASS="COMMAND"
>\pset linestyle
        old-ascii</TT
>.
       </P
></LI
><LI
><P
>        Allow <SPAN
CLASS="APPLICATION"
>psql</SPAN
> to use fancy Unicode line-drawing
        characters via <TT
CLASS="COMMAND"
>\pset linestyle unicode</TT
> (Roger Leigh)
       </P
></LI
></UL
></DIV
><DIV
CLASS="SECT5"
><H5
CLASS="SECT5"
><A
NAME="AEN109908"
>E.10.3.8.1.2. <SPAN
CLASS="APPLICATION"
>psql</SPAN
> <A
HREF="app-psql.html#APP-PSQL-META-COMMANDS"
><TT
CLASS="COMMAND"
>\d</TT
></A
>
     Commands</A
></H5
><P
></P
><UL
><LI
><P
>        Make <TT
CLASS="COMMAND"
>\d</TT
> show child tables that inherit from the specified
        parent (Damien Clochard)
       </P
><P
>        <TT
CLASS="COMMAND"
>\d</TT
> shows only the number of child tables, while
        <TT
CLASS="COMMAND"
>\d+</TT
> shows the names of all child tables.
       </P
></LI
><LI
><P
>        Show definitions of index columns in <TT
CLASS="COMMAND"
>\d index_name</TT
>
        (Khee Chin)
       </P
><P
>        The definition is useful for expression indexes.
       </P
></LI
><LI
><P
>        Show a view's defining query only in
        <TT
CLASS="COMMAND"
>\d+</TT
>, not in <TT
CLASS="COMMAND"
>\d</TT
> (Peter Eisentraut)
       </P
><P
>        Always including the query was deemed overly verbose.
       </P
></LI
></UL
></DIV
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109929"
>E.10.3.8.2. <A
HREF="app-pgdump.html"
><SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
></A
></A
></H4
><P
></P
><UL
><LI
><P
>       Make <SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
>/<SPAN
CLASS="APPLICATION"
>pg_restore</SPAN
>
       <A
HREF="app-pgdump.html#PG-DUMP-OPTIONS"
><TT
CLASS="OPTION"
>--clean</TT
></A
>
       also remove large objects (Itagaki Takahiro)
      </P
></LI
><LI
><P
>       Fix <SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
> to properly dump large objects when
       <TT
CLASS="LITERAL"
>standard_conforming_strings</TT
> is enabled (Tom Lane)
      </P
><P
>       The previous coding could fail when dumping to an archive file
       and then generating script output from <SPAN
CLASS="APPLICATION"
>pg_restore</SPAN
>.
      </P
></LI
><LI
><P
>       <SPAN
CLASS="APPLICATION"
>pg_restore</SPAN
> now emits large-object data in hex format
       when generating script output (Tom Lane)
      </P
><P
>       This could cause compatibility problems if the script is then
       loaded into a pre-9.0 server.  To work around that, restore
       directly to the server, instead.
      </P
></LI
><LI
><P
>       Allow <SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
> to dump comments attached to columns
       of composite types (Taro Minowa (Higepon))
      </P
></LI
><LI
><P
>       Make <SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
> <A
HREF="app-pgdump.html#PG-DUMP-OPTIONS"
><TT
CLASS="OPTION"
>--verbose</TT
></A
>
       output the <SPAN
CLASS="APPLICATION"
>pg_dump</SPAN
> and server versions
       in text output mode (Jim Cox, Tom Lane)
      </P
><P
>       These were already provided in custom output mode.
      </P
></LI
><LI
><P
>       <SPAN
CLASS="APPLICATION"
>pg_restore</SPAN
> now complains if any command-line arguments
       remain after the switches and optional file name (Tom Lane)
      </P
><P
>       Previously, it silently ignored any such arguments.
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109964"
>E.10.3.8.3. <A
HREF="app-pg-ctl.html"
><SPAN
CLASS="APPLICATION"
>pg_ctl</SPAN
></A
></A
></H4
><P
></P
><UL
><LI
><P
>       Allow <SPAN
CLASS="APPLICATION"
>pg_ctl</SPAN
> to be used safely to start the
       <SPAN
CLASS="APPLICATION"
>postmaster</SPAN
> during a system reboot (Tom Lane)
      </P
><P
>       Previously, <SPAN
CLASS="APPLICATION"
>pg_ctl</SPAN
>'s parent process could have been
       mistakenly identified as a running <SPAN
CLASS="APPLICATION"
>postmaster</SPAN
> based on
       a stale <SPAN
CLASS="APPLICATION"
>postmaster</SPAN
> lock file, resulting in a transient
       failure to start the database.
      </P
></LI
><LI
><P
>       Give <SPAN
CLASS="APPLICATION"
>pg_ctl</SPAN
> the ability to initialize the database
       (by invoking <SPAN
CLASS="APPLICATION"
>initdb</SPAN
>) (Zdenek Kotala)
      </P
></LI
></UL
></DIV
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN109981"
>E.10.3.9. <SPAN
CLASS="APPLICATION"
>Development Tools</SPAN
></A
></H3
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN109984"
>E.10.3.9.1. <A
HREF="libpq.html"
><SPAN
CLASS="APPLICATION"
>libpq</SPAN
></A
></A
></H4
><P
></P
><UL
><LI
><P
>       Add new <SPAN
CLASS="APPLICATION"
>libpq</SPAN
> functions
       <A
HREF="libpq-connect.html"
><CODE
CLASS="FUNCTION"
>PQconnectdbParams()</CODE
></A
>
       and <CODE
CLASS="FUNCTION"
>PQconnectStartParams()</CODE
> (Guillaume
       Lelarge)
      </P
><P
>       These functions are similar to <CODE
CLASS="FUNCTION"
>PQconnectdb()</CODE
> and
       <CODE
CLASS="FUNCTION"
>PQconnectStart()</CODE
> except that they accept a null-terminated
       array of connection options, rather than requiring all options to
       be provided in a single string.
      </P
></LI
><LI
><P
>       Add <SPAN
CLASS="APPLICATION"
>libpq</SPAN
> functions <A
HREF="libpq-exec.html#LIBPQ-EXEC-ESCAPE-STRING"
><CODE
CLASS="FUNCTION"
>PQescapeLiteral()</CODE
></A
>
       and <CODE
CLASS="FUNCTION"
>PQescapeIdentifier()</CODE
> (Robert Haas)
      </P
><P
>       These functions return appropriately quoted and escaped SQL string
       literals and identifiers. The caller is not required to pre-allocate
       the string result, as is required by <CODE
CLASS="FUNCTION"
>PQescapeStringConn()</CODE
>.
      </P
></LI
><LI
><P
>       Add support for a per-user service file (<A
HREF="libpq-pgservice.html"
><TT
CLASS="FILENAME"
>.pg_service.conf</TT
></A
>),
       which is checked before the site-wide service file
       (Peter Eisentraut)
      </P
></LI
><LI
><P
>       Properly report an error if the specified <SPAN
CLASS="APPLICATION"
>libpq</SPAN
> service
       cannot be found (Peter Eisentraut)
      </P
></LI
><LI
><P
>       Add <A
HREF="libpq-connect.html#LIBPQ-KEEPALIVES"
>TCP keepalive settings</A
>
       in libpq (Tollef Fog Heen, Fujii Masao, Robert Haas)
      </P
><P
>       Keepalive settings were already supported on the server end of
       TCP connections.
      </P
></LI
><LI
><P
>       Avoid extra system calls to block and unblock <TT
CLASS="LITERAL"
>SIGPIPE</TT
>
       in <SPAN
CLASS="APPLICATION"
>libpq</SPAN
>, on platforms that offer alternative methods
       (Jeremy Kerr)
      </P
></LI
><LI
><P
>       When a <A
HREF="libpq-pgpass.html"
><TT
CLASS="FILENAME"
>.pgpass</TT
></A
>-supplied
       password fails, mention where the password came from in the error
       message (Bruce Momjian)
      </P
></LI
><LI
><P
>       Load all SSL certificates given in the client certificate file
       (Tom Lane)
      </P
><P
>       This improves support for indirectly-signed SSL certificates.
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN110028"
>E.10.3.9.2. <A
HREF="ecpg.html"
><SPAN
CLASS="APPLICATION"
>ecpg</SPAN
></A
></A
></H4
><P
></P
><UL
><LI
><P
>       Add <A
HREF="ecpg-descriptors.html"
><ACRONYM
CLASS="ACRONYM"
>SQLDA</ACRONYM
></A
>
       (SQL Descriptor Area) support to <SPAN
CLASS="APPLICATION"
>ecpg</SPAN
>
       (Boszormenyi Zoltan)
      </P
></LI
><LI
><P
>       Add the <A
HREF="ecpg-descriptors.html"
><TT
CLASS="COMMAND"
>DESCRIBE</TT
>
       [ <TT
CLASS="LITERAL"
>OUTPUT</TT
> ]</A
> statement to <SPAN
CLASS="APPLICATION"
>ecpg</SPAN
>
       (Boszormenyi Zoltan)
      </P
></LI
><LI
><P
>       Add an <A
HREF="ecpg-library.html"
>ECPGtransactionStatus</A
>
       function to return the current transaction status (Bernd Helmle)
      </P
></LI
><LI
><P
>       Add the <TT
CLASS="LITERAL"
>string</TT
> data type in <SPAN
CLASS="APPLICATION"
>ecpg</SPAN
>
       Informix-compatibility mode (Boszormenyi Zoltan)
      </P
></LI
><LI
><P
>       Allow <SPAN
CLASS="APPLICATION"
>ecpg</SPAN
> to use <TT
CLASS="LITERAL"
>new</TT
> and <TT
CLASS="LITERAL"
>old</TT
>
       variable names without restriction (Michael Meskes)
      </P
></LI
><LI
><P
>       Allow <SPAN
CLASS="APPLICATION"
>ecpg</SPAN
> to use variable names in
       <CODE
CLASS="FUNCTION"
>free()</CODE
> (Michael Meskes)
      </P
></LI
><LI
><P
>       Make <CODE
CLASS="FUNCTION"
>ecpg_dynamic_type()</CODE
> return zero for non-SQL3 data
       types (Michael Meskes)
      </P
><P
>       Previously it returned the negative of the data type OID.
       This could be confused with valid type OIDs, however.
      </P
></LI
><LI
><P
>       Support <TT
CLASS="TYPE"
>long long</TT
> types on platforms that already have 64-bit
       <TT
CLASS="TYPE"
>long</TT
> (Michael Meskes)
      </P
></LI
></UL
><DIV
CLASS="SECT5"
><H5
CLASS="SECT5"
><A
NAME="AEN110068"
>E.10.3.9.2.1. <SPAN
CLASS="APPLICATION"
>ecpg</SPAN
> Cursors</A
></H5
><P
></P
><UL
><LI
><P
>        Add out-of-scope cursor support in <SPAN
CLASS="APPLICATION"
>ecpg</SPAN
>'s native mode
        (Boszormenyi Zoltan)
       </P
><P
>        This allows <TT
CLASS="COMMAND"
>DECLARE</TT
> to use variables that are not in
        scope when <TT
CLASS="COMMAND"
>OPEN</TT
> is called. This facility already existed
        in <SPAN
CLASS="APPLICATION"
>ecpg</SPAN
>'s Informix-compatibility mode.
       </P
></LI
><LI
><P
>        Allow dynamic cursor names in <SPAN
CLASS="APPLICATION"
>ecpg</SPAN
> (Boszormenyi Zoltan)
       </P
></LI
><LI
><P
>        Allow <SPAN
CLASS="APPLICATION"
>ecpg</SPAN
> to use noise words <TT
CLASS="LITERAL"
>FROM</TT
> and
        <TT
CLASS="LITERAL"
>IN</TT
> in <TT
CLASS="COMMAND"
>FETCH</TT
> and <TT
CLASS="COMMAND"
>MOVE</TT
> (Boszormenyi
        Zoltan)
       </P
></LI
></UL
></DIV
></DIV
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN110089"
>E.10.3.10. Build Options</A
></H3
><P
></P
><UL
><LI
><P
>      Enable client thread safety by default (Bruce Momjian)
     </P
><P
>      The thread-safety option can be disabled with <A
HREF="install-procedure.html#CONFIGURE"
><TT
CLASS="LITERAL"
>configure</TT
></A
>
      <TT
CLASS="OPTION"
>--disable-thread-safety</TT
>.
     </P
></LI
><LI
><P
>      Add support for controlling the Linux out-of-memory killer
      (Alex Hunsaker, Tom Lane)
     </P
><P
>      Now that <TT
CLASS="FILENAME"
>/proc/self/oom_adj</TT
> allows disabling
      of the <SPAN
CLASS="PRODUCTNAME"
>Linux</SPAN
> out-of-memory (<ACRONYM
CLASS="ACRONYM"
>OOM</ACRONYM
>)
      killer, it's recommendable to disable OOM kills for the postmaster.
      It may then be desirable to re-enable OOM kills for the postmaster's
      child processes.  The new compile-time option <A
HREF="kernel-resources.html#LINUX-MEMORY-OVERCOMMIT"
><TT
CLASS="LITERAL"
>LINUX_OOM_ADJ</TT
></A
>
      allows the killer to be reactivated for child processes.
     </P
></LI
></UL
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN110106"
>E.10.3.10.1. Makefiles</A
></H4
><P
></P
><UL
><LI
><P
>       New <TT
CLASS="FILENAME"
>Makefile</TT
> targets <A
HREF="install-procedure.html#BUILD"
><TT
CLASS="LITERAL"
>world</TT
></A
>,
       <TT
CLASS="LITERAL"
>install-world</TT
>, and <TT
CLASS="LITERAL"
>installcheck-world</TT
>
       (Andrew Dunstan)
      </P
><P
>       These are similar to the existing <TT
CLASS="LITERAL"
>all</TT
>, <TT
CLASS="LITERAL"
>install</TT
>,
       and <TT
CLASS="LITERAL"
>installcheck</TT
> targets, but they also build the
       <ACRONYM
CLASS="ACRONYM"
>HTML</ACRONYM
> documentation, build and test <TT
CLASS="FILENAME"
>contrib</TT
>,
       and test server-side languages and <SPAN
CLASS="APPLICATION"
>ecpg</SPAN
>.
      </P
></LI
><LI
><P
>       Add data and documentation installation location control to
       <ACRONYM
CLASS="ACRONYM"
>PGXS</ACRONYM
> Makefiles (Mark Cave-Ayland)
      </P
></LI
><LI
><P
>      Add Makefile rules to build the <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> documentation
      as a single <ACRONYM
CLASS="ACRONYM"
>HTML</ACRONYM
> file or as a single plain-text file
      (Peter Eisentraut, Bruce Momjian)
     </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN110130"
>E.10.3.10.2. Windows</A
></H4
><P
></P
><UL
><LI
><P
>       Support compiling on <A
HREF="install-windows.html"
>64-bit
       <SPAN
CLASS="PRODUCTNAME"
>Windows</SPAN
></A
> and running in 64-bit
       mode (Tsutomu Yamada, Magnus Hagander)
      </P
><P
>       This allows for large shared memory sizes on <SPAN
CLASS="PRODUCTNAME"
>Windows</SPAN
>.
      </P
></LI
><LI
><P
>       Support server builds using <A
HREF="install-windows-full.html"
><SPAN
CLASS="PRODUCTNAME"
>Visual Studio
       2008</SPAN
></A
> (Magnus Hagander)
      </P
></LI
></UL
></DIV
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN110143"
>E.10.3.11. Source Code</A
></H3
><P
></P
><UL
><LI
><P
>      Distribute prebuilt documentation in a subdirectory tree, rather than
      as tar archive files inside the distribution tarball
      (Peter Eisentraut)
     </P
><P
>      For example, the prebuilt <ACRONYM
CLASS="ACRONYM"
>HTML</ACRONYM
> documentation is now in
      <TT
CLASS="FILENAME"
>doc/src/sgml/html/</TT
>; the manual pages are packaged
      similarly.
     </P
></LI
><LI
><P
>      Make the server's lexer reentrant (Tom Lane)
     </P
><P
>      This was needed for use of the lexer by PL/pgSQL.
     </P
></LI
><LI
><P
>      Improve speed of memory allocation (Tom Lane, Greg Stark)
     </P
></LI
><LI
><P
>      User-defined constraint triggers now have entries in
      <TT
CLASS="STRUCTNAME"
>pg_constraint</TT
> as well as <TT
CLASS="STRUCTNAME"
>pg_trigger</TT
>
      (Tom Lane)
     </P
><P
>      Because of this change,
      <TT
CLASS="STRUCTNAME"
>pg_constraint</TT
>.<TT
CLASS="STRUCTFIELD"
>pgconstrname</TT
> is now
      redundant and has been removed.
     </P
></LI
><LI
><P
>      Add system catalog columns
      <TT
CLASS="STRUCTNAME"
>pg_constraint</TT
>.<TT
CLASS="STRUCTFIELD"
>conindid</TT
> and
      <TT
CLASS="STRUCTNAME"
>pg_trigger</TT
>.<TT
CLASS="STRUCTFIELD"
>tgconstrindid</TT
>
      to better document the use of indexes for constraint
      enforcement (Tom Lane)
     </P
></LI
><LI
><P
>      Allow multiple conditions to be communicated to backends using a single
      operating system signal (Fujii Masao)
     </P
><P
>      This allows new features to be added without a platform-specific
      constraint on the number of signal conditions.
     </P
></LI
><LI
><P
>      Improve source code test coverage, including <TT
CLASS="FILENAME"
>contrib</TT
>, PL/Python,
      and PL/Perl (Peter Eisentraut, Andrew Dunstan)
     </P
></LI
><LI
><P
>      Remove the use of flat files for system table bootstrapping
      (Tom Lane, Alvaro Herrera)
     </P
><P
>      This improves performance when using many roles or
      databases, and eliminates some possible failure conditions.
     </P
></LI
><LI
><P
>      Automatically generate the initial contents of
      <TT
CLASS="STRUCTNAME"
>pg_attribute</TT
> for <SPAN
CLASS="QUOTE"
>"bootstrapped"</SPAN
> catalogs
      (John Naylor)
     </P
><P
>      This greatly simplifies changes to these catalogs.
     </P
></LI
><LI
><P
>      Split the processing of
      <TT
CLASS="COMMAND"
>INSERT</TT
>/<TT
CLASS="COMMAND"
>UPDATE</TT
>/<TT
CLASS="COMMAND"
>DELETE</TT
> operations out
      of <TT
CLASS="FILENAME"
>execMain.c</TT
> (Marko Tiikkaja)
     </P
><P
>      Updates are now executed in a separate ModifyTable node.  This change is
      necessary infrastructure for future improvements.
     </P
></LI
><LI
><P
>      Simplify translation of <SPAN
CLASS="APPLICATION"
>psql</SPAN
>'s SQL help text
      (Peter Eisentraut)
     </P
></LI
><LI
><P
>      Reduce the lengths of some file names so that all file paths in the
      distribution tarball are less than 100 characters (Tom Lane)
     </P
><P
>      Some decompression programs have problems with longer file paths.
     </P
></LI
><LI
><P
>      Add a new <A
HREF="errcodes-appendix.html#ERRCODES-TABLE"
><TT
CLASS="LITERAL"
>ERRCODE_INVALID_PASSWORD</TT
></A
>
      <TT
CLASS="LITERAL"
>SQLSTATE</TT
> error code (Bruce Momjian)
     </P
></LI
><LI
><P
>      With authors' permissions, remove the few remaining personal source code
      copyright notices (Bruce Momjian)
     </P
><P
>      The personal copyright notices were insignificant but the community
      occasionally had to answer questions about them.
     </P
></LI
><LI
><P
>      Add new documentation <A
HREF="non-durability.html"
>section</A
>
      about running <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
> in non-durable mode
      to improve performance (Bruce Momjian)
     </P
></LI
><LI
><P
>      Restructure the <ACRONYM
CLASS="ACRONYM"
>HTML</ACRONYM
> documentation
      <TT
CLASS="FILENAME"
>Makefile</TT
> rules to make their dependency checks work
      correctly, avoiding unnecessary rebuilds (Peter Eisentraut)
     </P
></LI
><LI
><P
>      Use <SPAN
CLASS="PRODUCTNAME"
>DocBook</SPAN
> <ACRONYM
CLASS="ACRONYM"
>XSL</ACRONYM
> stylesheets for man page
      building, rather than <SPAN
CLASS="PRODUCTNAME"
>Docbook2X</SPAN
> (Peter Eisentraut)
     </P
><P
>      This changes the set of tools needed to build the man pages.
     </P
></LI
><LI
><P
>      Improve PL/Perl code structure (Tim Bunce)
     </P
></LI
><LI
><P
>      Improve error context reports in PL/Perl (Alexey Klyukin)
     </P
></LI
></UL
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN110222"
>E.10.3.11.1. New Build Requirements</A
></H4
><P
>      Note that these requirements do not apply when building from a
      distribution tarball, since tarballs include the files that these
      programs are used to build.
     </P
><P
></P
><UL
><LI
><P
>       Require <SPAN
CLASS="APPLICATION"
>Autoconf</SPAN
> 2.63 to build
       <SPAN
CLASS="APPLICATION"
>configure</SPAN
> (Peter Eisentraut)
      </P
></LI
><LI
><P
>       Require <SPAN
CLASS="APPLICATION"
>Flex</SPAN
> 2.5.31 or later to build
       from a <ACRONYM
CLASS="ACRONYM"
>CVS</ACRONYM
> checkout (Tom Lane)
      </P
></LI
><LI
><P
>       Require <SPAN
CLASS="APPLICATION"
>Perl</SPAN
> version 5.8 or later to build
       from a <ACRONYM
CLASS="ACRONYM"
>CVS</ACRONYM
> checkout (John Naylor, Andrew Dunstan)
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN110238"
>E.10.3.11.2. Portability</A
></H4
><P
></P
><UL
><LI
><P
>       Use a more modern <ACRONYM
CLASS="ACRONYM"
>API</ACRONYM
> for <SPAN
CLASS="APPLICATION"
>Bonjour</SPAN
> (Tom Lane)
      </P
><P
>       Bonjour support now requires <SPAN
CLASS="PRODUCTNAME"
>OS X</SPAN
> 10.3 or later.
       The older API has been deprecated by Apple.
      </P
></LI
><LI
><P
>       Add spinlock support for the <SPAN
CLASS="PRODUCTNAME"
>SuperH</SPAN
>
       architecture (Nobuhiro Iwamatsu)
      </P
></LI
><LI
><P
>       Allow non-<SPAN
CLASS="APPLICATION"
>GCC</SPAN
> compilers to use inline functions if
       they support them (Kurt Harriman)
      </P
></LI
><LI
><P
>       Remove support for platforms that don't have a working 64-bit
       integer data type (Tom Lane)
      </P
></LI
><LI
><P
>       Restructure use of <TT
CLASS="LITERAL"
>LDFLAGS</TT
> to be more consistent
       across platforms (Tom Lane)
      </P
><P
>       <TT
CLASS="LITERAL"
>LDFLAGS</TT
> is now used for linking both executables and shared
       libraries, and we add on <TT
CLASS="LITERAL"
>LDFLAGS_EX</TT
> when linking
       executables, or <TT
CLASS="LITERAL"
>LDFLAGS_SL</TT
> when linking shared libraries.
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN110262"
>E.10.3.11.3. Server Programming</A
></H4
><P
></P
><UL
><LI
><P
>       Make backend header files safe to include in <SPAN
CLASS="PRODUCTNAME"
>C++</SPAN
>
       (Kurt Harriman, Peter Eisentraut)
      </P
><P
>       These changes remove keyword conflicts that previously made
       <SPAN
CLASS="PRODUCTNAME"
>C++</SPAN
> usage difficult in backend code.  However, there
       are still other complexities when using <SPAN
CLASS="PRODUCTNAME"
>C++</SPAN
> for backend
       functions. <TT
CLASS="LITERAL"
>extern "C" { }</TT
> is still necessary in
       appropriate places, and memory management and error handling are
       still problematic.
      </P
></LI
><LI
><P
>       Add <A
HREF="xaggr.html"
><CODE
CLASS="FUNCTION"
>AggCheckCallContext()</CODE
></A
>
       for use in detecting if a <SPAN
CLASS="PRODUCTNAME"
>C</SPAN
> function is
       being called as an aggregate (Hitoshi Harada)
      </P
></LI
><LI
><P
>       Change calling convention for <CODE
CLASS="FUNCTION"
>SearchSysCache()</CODE
> and related
       functions to avoid hard-wiring the maximum number of cache keys
       (Robert Haas)
      </P
><P
>       Existing calls will still work for the moment, but can be expected to
       break in 9.1 or later if not converted to the new style.
      </P
></LI
><LI
><P
>       Require calls of <CODE
CLASS="FUNCTION"
>fastgetattr()</CODE
> and
       <CODE
CLASS="FUNCTION"
>heap_getattr()</CODE
> backend macros to provide a non-NULL fourth
       argument (Robert Haas)
      </P
></LI
><LI
><P
>       Custom typanalyze functions should no longer rely on
       <TT
CLASS="STRUCTNAME"
>VacAttrStats</TT
>.<TT
CLASS="STRUCTFIELD"
>attr</TT
> to determine the type
       of data they will be passed (Tom Lane)
      </P
><P
>       This was changed to allow collection of statistics on index columns
       for which the storage type is different from the underlying column
       data type.  There are new fields that tell the actual datatype being
       analyzed.
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN110290"
>E.10.3.11.4. Server Hooks</A
></H4
><P
></P
><UL
><LI
><P
>       Add parser hooks for processing ColumnRef and ParamRef nodes
       (Tom Lane)
      </P
></LI
><LI
><P
>       Add a ProcessUtility hook so loadable modules can control utility
       commands (Itagaki Takahiro)
      </P
></LI
></UL
></DIV
><DIV
CLASS="SECT4"
><H4
CLASS="SECT4"
><A
NAME="AEN110297"
>E.10.3.11.5. Binary Upgrade Support</A
></H4
><P
></P
><UL
><LI
><P
>      Add <A
HREF="pgupgrade.html"
><TT
CLASS="FILENAME"
>contrib/pg_upgrade</TT
></A
>
      to support in-place upgrades (Bruce Momjian)
     </P
><P
>      This avoids the requirement of dumping/reloading the database when
      upgrading to a new major release of PostgreSQL, thus reducing downtime
      by orders of magnitude. It supports upgrades to 9.0
      from PostgreSQL 8.3 and 8.4.
     </P
></LI
><LI
><P
>       Add support for preserving relation <A
HREF="catalog-pg-class.html"
><TT
CLASS="STRUCTNAME"
>relfilenode</TT
></A
> values
       during binary upgrades (Bruce Momjian)
      </P
></LI
><LI
><P
>       Add support for preserving <TT
CLASS="STRUCTNAME"
>pg_type</TT
>
       and <TT
CLASS="STRUCTNAME"
>pg_enum</TT
> OIDs during binary upgrades
       (Bruce Momjian)
      </P
></LI
><LI
><P
>       Move data files within tablespaces into
       <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>-version-specific subdirectories
       (Bruce Momjian)
      </P
><P
>       This simplifies binary upgrades.
      </P
></LI
></UL
></DIV
></DIV
><DIV
CLASS="SECT3"
><H3
CLASS="SECT3"
><A
NAME="AEN110317"
>E.10.3.12. Contrib</A
></H3
><P
></P
><UL
><LI
><P
>      Add multithreading option (<TT
CLASS="OPTION"
>-j</TT
>) to <A
HREF="pgbench.html"
><TT
CLASS="FILENAME"
>contrib/pgbench</TT
></A
>
      (Itagaki Takahiro)
     </P
><P
>      This allows multiple <ACRONYM
CLASS="ACRONYM"
>CPU</ACRONYM
>s to be used by pgbench,
      reducing the risk of pgbench itself becoming the test bottleneck.
     </P
></LI
><LI
><P
>      Add <TT
CLASS="COMMAND"
>\shell</TT
> and <TT
CLASS="COMMAND"
>\setshell</TT
> meta
      commands to <A
HREF="pgbench.html"
><TT
CLASS="FILENAME"
>contrib/pgbench</TT
></A
>
      (Michael Paquier)
     </P
></LI
><LI
><P
>      New features for <A
HREF="dict-xsyn.html"
><TT
CLASS="FILENAME"
>contrib/dict_xsyn</TT
></A
>
      (Sergey Karpov)
     </P
><P
>      The new options are <TT
CLASS="LITERAL"
>matchorig</TT
>, <TT
CLASS="LITERAL"
>matchsynonyms</TT
>,
      and <TT
CLASS="LITERAL"
>keepsynonyms</TT
>.
     </P
></LI
><LI
><P
>      Add full text dictionary <A
HREF="unaccent.html"
><TT
CLASS="FILENAME"
>contrib/unaccent</TT
></A
>
      (Teodor Sigaev)
     </P
><P
>      This filtering dictionary removes accents from letters, which
      makes full-text searches over multiple languages much easier.
     </P
></LI
><LI
><P
>      Add <A
HREF="contrib-dblink-get-notify.html"
><CODE
CLASS="FUNCTION"
>dblink_get_notify()</CODE
></A
>
      to <TT
CLASS="FILENAME"
>contrib/dblink</TT
> (Marcus Kempe)
     </P
><P
>      This allows asynchronous notifications in <SPAN
CLASS="PRODUCTNAME"
>dblink</SPAN
>.
     </P
></LI
><LI
><P
>      Improve <TT
CLASS="FILENAME"
>contrib/dblink</TT
>'s handling of dropped columns
      (Tom Lane)
     </P
><P
>      This affects <A
HREF="contrib-dblink-build-sql-insert.html"
><CODE
CLASS="FUNCTION"
>dblink_build_sql_insert()</CODE
></A
>
      and related functions.  These functions now number columns according
      to logical not physical column numbers.
     </P
></LI
><LI
><P
>      Greatly increase <A
HREF="hstore.html"
><TT
CLASS="FILENAME"
>contrib/hstore</TT
></A
>'s data
      length limit, and add B-tree and hash support so <TT
CLASS="LITERAL"
>GROUP
      BY</TT
> and <TT
CLASS="LITERAL"
>DISTINCT</TT
> operations are possible on
      <TT
CLASS="TYPE"
>hstore</TT
> columns (Andrew Gierth)
     </P
><P
>      New functions and operators were also added.  These improvements
      make <TT
CLASS="TYPE"
>hstore</TT
> a full-function key-value store embedded in
      <SPAN
CLASS="PRODUCTNAME"
>PostgreSQL</SPAN
>.
     </P
></LI
><LI
><P
>      Add <A
HREF="passwordcheck.html"
><TT
CLASS="FILENAME"
>contrib/passwordcheck</TT
></A
>
      to support site-specific password strength policies (Laurenz
      Albe)
     </P
><P
>      The source code of this module should be modified to implement
      site-specific password policies.
     </P
></LI
><LI
><P
>      Add <A
HREF="pgarchivecleanup.html"
><TT
CLASS="FILENAME"
>contrib/pg_archivecleanup</TT
></A
>
      tool (Simon Riggs)
     </P
><P
>      This is designed to be used in the
      <TT
CLASS="LITERAL"
>archive_cleanup_command</TT
>
      server parameter, to remove no-longer-needed archive files.
     </P
></LI
><LI
><P
>      Add query text to <A
HREF="auto-explain.html"
><TT
CLASS="FILENAME"
>contrib/auto_explain</TT
></A
>
      output (Andrew Dunstan)
     </P
></LI
><LI
><P
>      Add buffer access counters to <A
HREF="pgstatstatements.html"
><TT
CLASS="FILENAME"
>contrib/pg_stat_statements</TT
></A
>
      (Itagaki Takahiro)
     </P
></LI
><LI
><P
>      Update <A
HREF="server-start.html"
><TT
CLASS="FILENAME"
>contrib/start-scripts/linux</TT
></A
>
      to use <TT
CLASS="FILENAME"
>/proc/self/oom_adj</TT
> to disable the
      <A
HREF="kernel-resources.html#LINUX-MEMORY-OVERCOMMIT"
><SPAN
CLASS="PRODUCTNAME"
>Linux</SPAN
>
      out-of-memory</A
> (<ACRONYM
CLASS="ACRONYM"
>OOM</ACRONYM
>) killer (Alex
      Hunsaker, Tom Lane)
     </P
></LI
></UL
></DIV
></DIV
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